what does
#sh route
give you
to specify the default gateway, or default route, the command lrmoore stated is all you need, then run the sh route like I said to just confirm it is in fact set right
after that do a
#wr mem
to save the config
btw, the 10.10.8.1 is the internal gateway which points to the pix, so the pix shouldn't be pointing to itself, rather just needs a route to the internal network which it creates after you had assigned the internal ip (called a connect route since it learns it from having that connected directly to it on an interface)