The VA based casting/production company Team Jabberwocky has posted over a hundred aspiring actors auditions online. They also posted the contact details for the actors, so you don't have to pay to get in touch with them.

Even if you're not looking for actors right now, you can get bit of an insight into the auditioning process.

http://www.youtube.com/user/StonehengeAuditions

Full disclosure: My girlfriend (http://www.youtube.com/watch?v=BdTya7YfMPc) was one of the auditions, otherwise I have no connection to this.

for anyone who might be wondering, these were shot on a panasonic