you should be able to place any CPU out of these:
taken from http://en.wikipedia.org/wiki/Socket_P
you can also check out Intel's ARK for any processor since the Pentium I,
here's the T3400 for you, socket P, should be fully compatible.
there seems to be a great deal of confusion here,
there seems to be 2 celeron 530's which one of is M and the other is simply called a celeron 530.
the 530M is a socket M 478 and the 530 is a socket P, they are both released with a 1733 clock speed just not pin compatible.
with the wiki article and crossed with newegg,
the T5300 processor is compatible with socket M (or PPGA478) apparently and not socket P,
(yet to add to the confusion, it seems that socket P is also called socket PPGA478..)
and so, by what you'r saying, your acer isn't compatible with it.
the T2330 and T3400 should be compatible with your socket and are listed as socket P processors,
the Pentium SL7SL is listed as socket 479 and dated at 2005,
socket P was issued only at 2007 so they should not be compatible.
you can check out further processors from the list, it might come in handy,
notice processors listed either as socket P or released after 2007 as earlier should be compatible only with socket M, the micro architecture is said to be core for all and not any netburst processors, so the only performance difference should be cache and clock speed.
this should be it .