It looks as though I can implement a site to site vpn even if both sides 
have a dynamic ip address. (SBC DSL connection on both sides) My question is 
does the tunnel stay up when the ip address is in the process of changing? 
Is it down for a split second etc?

Also, I am wondering if I can prioritize the traffic bound for the ipsec vpn 
higher than the web traffic. If so, how? I haven't used traffic shaping at 
all and I'm not sure how to do this yet.

Thanks.