If I wanted the ability to check if a domain name is available from my site how do I go about doing that?

do you mean for youself or for your clients?

for my clients. you see them on most reseller sites where they check to see if a name is free or not.

This is a pretty good script and easy to integrate with your site:
http://www.mattsscripts.co.uk/mwhois.htm

Cool, thanks Loon.

Do a WHOIS check

If you use PHP-Nuke, or the like, you can try NSN Whois. It ties in great with a Nuke powered site

going to have to see if this will work in a e107 site. i should beable to let u know. thanks

I'd recommend CDomain.com. It's pretty simple to set up.