What you're looking for is known as "Singable English Lyrics".
anshkakashi (and Rody!) over at
Tokyo-Nights are doing a project to "translate" all the best Ayumi songs into SELs:
http://www.tokyo-nights.org/forum/showthread.php?t=337
They've done an impressive 17 songs so far, with Karaoke PVs to follow. They work really well, just don't let your neighbours hear you practicing!