It's really annoying when you got softbrick hahaha.
but yah, like lumin said, what ROM u use when u soft brick ur phone.
WIPING EVERYTHING THEN FLASH UR ROM
will fix softbrick just backup ur files on ur SD or
WIPE SYSTEM-DATA-CACHE-DALVIK FLASH ROM
will fix also but no need to backup SD files
that method always saves me from softbrick..
PHONE: Samsung Galaxy S 4G
ROM: SLIMSABER BETA
MODEM: KG4 MODEM