dengdeng, i don't think that "apr - july is 4 months, 120 days is the maximum name checking time)." is true.
mine was sent to fbi on 3/8/03, and now it's 7/24/03. yesterday i went to local office and asked an officer, she said it's normal and she personally knew ppl waiting since this jan.
i don't know if this check is the same as the one for visa applications (f1, b2, etc.), but for those, i know ppl wait for 3-6 months.
i tried to contact fbi headquarter and field office, but no one could tell me where to check in fbi (or there'is no call-in service).