There's still no info as of yet about the track selections for each album, but we do know who is working on each now. The Rock Arrange Version will include the work of Kenji Ito (Mana, SaGa), Kazuki Ohta (FFXII, Valkyria Chronicles 3), Mitsuhiro Kandea (Odin Sphere, Tekken 6), Yoshimi Kudo (Tekken 6), Tetsuro Sato (Psyvariar), Hitoshi Sakimoto (Tactics Ogre, Breath of Fire V), Hiroshi Tanabe (The Prince of Tennis), Azusa Chiba (Let's TAP), Yoshitaka Hirota (Chrono Trigger), and LivestRow. Meanwhile the Techno Arrange Version has Masahiro Iwata (Mushihimesama), Mitsuhiro Kaneda, Yoshimi Kudo, Hitoshi Sakimoto, Denji Sano (Love Synthesizer!), Yuto Takei (Gran Turismo 5), Azusa Chiba, Takeshi Hama (Devil May Cry), Far East Recording and Shinji Hosoe (Mega Man Network Transmission).
Hopefully more info will be coming soon. For now, TEAM Entertainment has setup this nifty little homepage for both soundtracks.
UPDATE: Although the track lists still aren't known, there may be a hint. The covers seem to feature sprites of Robot Masters. The Rock Arrange Version has Heat, Bubble, Wood, Air, Crash, Metal and Elec, and the Techno Arrange Version has Heat, Skull, Pharaoh, Hard, Quick, Snake and Flash. However, there are some oddities with this. First off, it implies a heavy amount of focus on Mega Man 2; and Heat Man's theme twice? Furthermore, some of the sprites seem to look... just odd, as if they were distorted or custom drawn. Until more information comes to light, I wouldn't say these sprites represent the album tracks for certain.