You can buy everything on eBay. I believe the Fuji can be purchased in stores. The Impossible Project still have old stock left of the original Polaroid film. I ran a pack through a camera yesterday, and it's great (although you do get quite small pictures...)
For pack film (100/200/300/400 Automatic, 185/190 manual and 600SE) Fuji still makes FP-3000B high speed BW and while discontinued (sad!) you can still get Nov/Dec 2011 expiring FP-100B as well. You can also get expired Polaroid 665 on eBay and amazon.
For integral film Impossible project makes some Silver Shade and eBay and amazon still sell some from Polaroid's last runs.