Yamaha and other companies are releasing several scorebooks that include Vocaloid (and related) songs. Here is a summary of them with links. Listed below are piano sheet music, band scores, and guitar scores.
Band Score Vocaloid Best Collection Price: 1,680 yen release date: 3/24 http://www.amazon.co.jp/exec/obidos/ASIN/4636885309/i22-22/ref=nosim/ Songs: Tell Your World / World is Mine / Miku Miku ni Shite Ageru♪ (Shiteyanyo) / Melt / Just Be Friends / Black★Rock Shooter / Mozaik Role / World End Dance Hall / Romeo to Cinderella / Roshin Yuukai / Invisible / Uraomote Lovers / Koi wa Sensou / Rolling Girl / Panda Hero / Yowamushi Mont Blanc / Hajimete no Oto / Senbonzakura / Uta ni Katachi wa nai Keredo / Sakura no Ame / Hajimete no Koi ga Owaru Toki / 1925 / magnet / E? Aa, Sou / Ama no Jaku / Kagerou Days / Tori no Ai Uta / Twinkle / Kokoro / Aimai Elegy / Koisuru VOC@LOID / for a total of 30 songs
Piano Solo Yasashiku Hikeru Vocaloid Selection for Piano (Easy Level Scores) Price: 1,575 yen Release Date: 3/16 http://www.amazon.co.jp/exec/obidos/ASIN/4636885260/i22-22/ref=nosim/ Songs: Melt (supercell), magnet (minato(RyuuseiP)), Roshin Yuukai (iroha(sasaki)), Romeo to Cinderella (doriko), Just Be Friends (Dixie Flatline), Hajimete no Oto (malo), Miku Miku ni Shite Ageru (Shinteyanyo) (ika), Ai Kotoba (DECO*27), Time Machine (1640mP (164x40mP)), Kokoro (ToraborutaP), ARiA (TokuP), Double Lariat (Agoaniki), 1925 (T-POCKET), for a total of 14 songs
Piano Solo Chuukyuu Piano de Hiku Hatsune Miku, Kagamine Rin & Len, Megurine Luka no Uta (Intermediate level scores) Price: 1,575 yen Release Date: 3/16 http://www.amazon.co.jp/exec/obidos/ASIN/4636885279/i22-22/ref=nosim/ Songs: Hatsune Miku no Gekisou (Storyteller (GAiA x cosMo@BousouP)), Ai Kotoba (DECO*27), Miku Miku ni Shite Ageru (Shiteyanyo) (ika), Hajimete no Oto (malo), Double Lariat (Agoaniki), 1925 (T-POCKET), Migikata no Chou (NoriP), Kokoro (Toraboruta), Time Machine (1640mP (164x40mP)), ARiA (TokuP), for a total of 10 songs
Guitar Score VOCALOID Best Collection Price: 1,890 Release Date: 3/24 http://www.amazon.co.jp/exec/obidos/ASIN/4636885317/i22-22/ref=nosim/ Songs: Mikumiku ni Shite Ageru, Melt, World is Mine, Just Be Friends, Black Rock Shooter, Mozaik Role, World's End Dance Hall, Romeo to Cinderella, Roshin Yuukai, Invisible, Uraomote Lovers, Koi wa Sensou, Rolling Girl, Panda Hero, Yowamushi Mont Blanc, Hajimete no Oto, Senbonzakura, Uta ni Katachi wa nai Keredo, Sakura no Ame, Hajimete no Koi ga Owaru Toki, 1925, magnet, E? Aa, Sou., Ama no Jaku, Kagerou Days, Tori no Ai Uta, Twinkle, Kokoro, Aimai Elegy, Aisuru Voc@loid, for a total of 30 songs
[Vocalo/Book] Various Score Books [updated 3/19]
Band Score Vocaloid Best Collection
Price: 1,680 yen
release date: 3/24
http://www.amazon.co.jp/exec/obidos/ASIN/4636885309/i22-22/ref=nosim/
Songs: Tell Your World / World is Mine / Miku Miku ni Shite Ageru♪ (Shiteyanyo) / Melt / Just Be Friends / Black★Rock Shooter / Mozaik Role / World End Dance Hall / Romeo to Cinderella / Roshin Yuukai / Invisible / Uraomote Lovers / Koi wa Sensou / Rolling Girl / Panda Hero / Yowamushi Mont Blanc / Hajimete no Oto / Senbonzakura / Uta ni Katachi wa nai Keredo / Sakura no Ame / Hajimete no Koi ga Owaru Toki / 1925 / magnet / E? Aa, Sou / Ama no Jaku / Kagerou Days / Tori no Ai Uta / Twinkle / Kokoro / Aimai Elegy / Koisuru VOC@LOID / for a total of 30 songs
Band Score supercell "Kokuhaku / Bokura no Ashiato"
Price: 1,260 yen
Release Date: 3/18
http://www.amazon.co.jp/exec/obidos/ASIN/4636885295/i22-22/ref=nosim/
Piano Solo Yasashiku Hikeru Vocaloid Selection for Piano (Easy Level Scores)
Price: 1,575 yen
Release Date: 3/16
http://www.amazon.co.jp/exec/obidos/ASIN/4636885260/i22-22/ref=nosim/
Songs: Melt (supercell), magnet (minato(RyuuseiP)), Roshin Yuukai (iroha(sasaki)), Romeo to Cinderella (doriko), Just Be Friends (Dixie Flatline), Hajimete no Oto (malo), Miku Miku ni Shite Ageru (Shinteyanyo) (ika), Ai Kotoba (DECO*27), Time Machine (1640mP (164x40mP)), Kokoro (ToraborutaP), ARiA (TokuP), Double Lariat (Agoaniki), 1925 (T-POCKET), for a total of 14 songs
Piano Solo Chuukyuu Piano de Hiku Hatsune Miku, Kagamine Rin & Len, Megurine Luka no Uta (Intermediate level scores)
Price: 1,575 yen
Release Date: 3/16
http://www.amazon.co.jp/exec/obidos/ASIN/4636885279/i22-22/ref=nosim/
Songs: Hatsune Miku no Gekisou (Storyteller (GAiA x cosMo@BousouP)), Ai Kotoba (DECO*27), Miku Miku ni Shite Ageru (Shiteyanyo) (ika), Hajimete no Oto (malo), Double Lariat (Agoaniki), 1925 (T-POCKET), Migikata no Chou (NoriP), Kokoro (Toraboruta), Time Machine (1640mP (164x40mP)), ARiA (TokuP), for a total of 10 songs
Gekkan Piano 2012 Nen 4 Gatsu Gou (Magazine)
http://www.amazon.co.jp/exec/obidos/ASIN/B007BYXUU0/i22-22/ref=nosim/
Price: 650 yen
Release Date: 3/19
Features various J-Pop songs, including livetune's "Tell Your World"
Guitar Score VOCALOID Best Collection
Price: 1,890
Release Date: 3/24
http://www.amazon.co.jp/exec/obidos/ASIN/4636885317/i22-22/ref=nosim/
Songs: Mikumiku ni Shite Ageru, Melt, World is Mine, Just Be Friends, Black Rock Shooter, Mozaik Role, World's End Dance Hall, Romeo to Cinderella, Roshin Yuukai, Invisible, Uraomote Lovers, Koi wa Sensou, Rolling Girl, Panda Hero, Yowamushi Mont Blanc, Hajimete no Oto, Senbonzakura, Uta ni Katachi wa nai Keredo, Sakura no Ame, Hajimete no Koi ga Owaru Toki, 1925, magnet, E? Aa, Sou., Ama no Jaku, Kagerou Days, Tori no Ai Uta, Twinkle, Kokoro, Aimai Elegy, Aisuru Voc@loid, for a total of 30 songs
Piano Solo/Hikigatari "Tell Your World EP" livetune feat. Hatsune Miku
Price: 1,260
Release Date: 3/25
http://www.amazon.co.jp/exec/obidos/ASIN/4636885457/i22-22/ref=nosim/
Band Score Hatsune Miku Selection
Price: 2,100
Release Date: 4/22
http://www.amazon.co.jp/exec/obidos/ASIN/477323489X/i22-22/ref=nosim/
Songs: TBA