heya sven - shin megami tensei 1 and 2 have been given fan translations, you can find the patches for the roms here:
http://agtp.romhack.net/project.php?id=smt http://agtp.romhack.net/project.php?id=smt2 just a bit of warning, though - if you play the *first* game on the side of Law, dont expect to be able to beat it without using a cheat. unfortunately, when they were working on releasing the patch, the fellow who did the play testing of the Law side of things... eh, apparently flaked out and didnt bother to finish the game. so, later in the game, if you're Law, it glitches and you'll be unable to progress any farther. but if you do an alignment cheat (seems a number of emulators have code systems built in) to change your alignment to something else, then back to Law after the iffy part, should be fine.
as of yet, that's all of the rom translations, i'm afraid - the group that released the above two titles *was* working on a lot of other translations, including the original nes megami tensei, majin tensei 1 and 2 (the two strategy titles in the series), and even a translation for the playstation version of Devil Summoner: Soul Hackers... but all have been on hiatus for *years* now, and i doubt they'll ever be completed (still, you never know - they're still up in the "current projects" section of that site).
also of note - in the past, a group of delightful ladies made a script which translated basically all of the important dialogue of Persona 2: Innocent Sin (which didnt come out in north america, though the second part of Persona 2 - "Eternal Punishment" DID get released). but they've removed the script now
but some other people, who i know nothing about, went and released a FULL english *patch* for the game late last year! ... which i cant play, because apparently it doesnt work with the particular version of the game i have
but if you ever get your hands on a copy of that game (not the "The Best" version, which i have), you might want to give it a shot.