Court Jurisdiction and the Internet

I am a law student studying how a citizen of a state
can subject himself to the jurisdiction of a foreign court though
web-related activites.

Where may I find technical information related to the
possibility of limiting access to a web site by geography?

For example, if I have a web site in Texas, U.S., is there
a proposed mechanism or addressing scheme for limiting access of
a web site to citizens of selected states or countries?

I would appreciate any information/links that you can provide.
Thanks in advance.
-- 

Michael R. Sees, P.E.
sees@netcom.com