ok, so 2.8 with HT (and assuming LGA775) makes your chip one of these
SL7J4 2.80 GHz 520 1 800 MHz 90 nm D0 1 MB LGA775 04A
SL7J5 2.80 GHz 520 1 800 MHz 90 nm D0 1 MB LGA775 04A
SL9CG 2.80 GHz 521 1 800 MHz 90 nm G1 1 MB LGA775 04A
SL8HX 2.80 GHz 521 1 800 MHz 90 nm E0 1 MB LGA775 04A
SL8PP 2.80 GHz 521 1 800 MHz 90 nm G1 1 MB LGA775 04A
SL7PR 2.80 GHz 520J 1 800 MHz 90 nm E0 1 MB LGA775 04A
SL7KJ 2.80 GHz 520 1 800 MHz 90 nm D0 1 MB LGA775 04A
SL8AB 2.80 GHz 620 1 800 MHz 90 nm N0 2 MB LGA775 04A
the PCG on those is 04A - you just have to check that your board would support that. note that the P45 boards i was looking at only supported the newer 05 and 06 PCGs.
Edit: and to answer your original question, yes, the Abit IP35-E does support this chip - on the
'supported cpu' page that Jessica69 posted, the Pentium 4 521/520/J is waaaay down at the bottom of the list. For other boards, you just have to look at the specs from the vendor to know whether your chip is supported.