Pretty cool. If you aren't familiar with these guys, they are the kings of do-it-yourself casting:
http://www.backyardmetalcasting.com/
Let me give you a bit of advice, though. I've taken classes and cast aluminum, bronze and even iron. Those processes are inherently dangerous and really should be done under supervision the first few times.
Pewter, however, is relatively safe if you use the lead-free variants. For that matter, there are numerous resins that present no danger of death-by-fire.
What I'm saying is that you should consider starting out on low temperature metals or resins, refine your process, then proceed to aluminum. After that you can do the higher temperature alloys.
Safety first, and believe me... casting can go bad quickly. I have a shirt that is covered in pewter because of my lack of care one afternoon. I keep that shirt as a reminder that if I hadn't been wearing glasses that day I would have probably lost an eye.
"Just this once" is the most dangerous phrase on the planet.