The Asus P4T533-C supports 400 and 533MHz FSB. You can download the manual <A HREF="http://www.asus.com.tw/support/download/selectftp.aspx?l1_id=1&l2_id=15&l3_id=5&m_id=3&f_name=e1222_p4t533-c.pdf" target="_new">here</A>.
You can use any p4 up to the 3.06 GHz with hyper-threading. It's $370 at <A HREF="http://www.newegg.com/app/viewproduct.asp?description=19-116-154&refer=pricewatch" target="_new">Newegg</A> which is a pretty good deal. Prices on the 3.06 GHz P4 really dropped now that the P4 C's have arrived.
It's $371 at <A HREF="http://www.googlegear.com/jsp/ProductDetail.jsp?ProductCode=80660" target="_new">Googlegear</A>.
Both are retail package, 3 year warranty and both are in stock. Go for it!