abstract url's

[suluclac]

Has anyone implemented what some call "abstract url's"?
To clarify, I would like my pages to be called like this:
http://www.domainname.com/dir/file

and NOT like this:
http://www.domainname.com/dir/file.cfm

One clear advantage of this is that if I decide to change programming languages, this change will break all of the links from other sites to mine. That's a big problem.
Another reason could possibly be security. Why should anyone know that i'm using CF?

I'd like to hear peoples suggestions. Some direction would be appreciated.
Thanks!

[Stressed_Simon]

It depends which webserver you are on? If you are on Apache look into mod_rewrite, or if you are on IIS look into ISAPI rewrite.

[suluclac]

Well, that means if i'm in a shared environment i'm screwed.
Have you heard of this being done in the application code?