If it's an AGP Voodoo Banshee, 3 or 5 then no. If it's an AGP Voodoo4 or any PCI cards then yes.
If your card has the top two notches they will fry the P4 mobo (that's if they fit), the bottom one will work. Please note the notch at the bottom can be found on some ATi 7500 and SiS video cards that will fit in a P4 AGP slot, but destroy your mobo so be careful. [Image: http://www.pcreport.de/online2001/bilder/agp-varianten.jpg]
Actually, I might as well get a new case while I'm getting all this new stuff so I'll throw in a case with a 250W P4 P/Supply. The case is just a Liang Ling (Spelling???) plain beige case. It has 3 external 5 1/4 and 3 internal 3 1/2 and 2 slots for FDD's.