The tg3 in Fedora Core 1 Test #3 doesn't support the newer Broadcom bcm5705 and bcm5705M chips used in e.g. Dell Latitude D800 laptops. Support for these chips was added to tg3 around kernel 2.6.0-test4 (by jgarzik and davem according to bkbits). Relevant revisions of tg3.c are 1.83 through 1.98 (or thereabouts).
Updated tg3 driver in current rawhide kernel