Okey, tried to Kanji>Romaji the songs, please don't bash me if I'm wrong, I'm no professional. ^__^;;
[Daburureinbou (Double Rainbow)]
1. Zutto Suki Ii Desu ka?
Lyrics: Tsunku - Composer: Imai Chihiro
2. Colorful
Lyrics/Composer: Ozaki Ami
3. Ki ga Tsukeba Anata
Lyrics/Composer: Tsunku
4. Latin Lover
Lyrics: Makoto - Composer: Hatake
5. Melodies (Matsuura Version)
Lyrics/Composer: Tsunku
6. Kurutta Kajitsu
Lyrics/Composer: Yokoyama Terukazu
7. Me wo Tojite Oide yo (With TAKERU)
Lyrics/Composer: Imamichi Tomotaka
8. New York Monogatari
Lyrics/Composer: Tsunku
9. DOUBLE RAINBOW
Lyrics: TAKAHIRO MAEDA Composer: TETSUYA KOMURO
10. Egao
Lyrics/Composer: Tanimura Yumi
11. Mirai
Lyrics: Makoto Composer: Taise
12. YOUR SONG ~Seishun Sensei~ (Album Version)
Lyrics/Composer: Tsunku
13. Yotsuba no Clover
Lyrics/Composer: BULGE
13, songs? That's alot. O__o