Sticky URL

Dear all

I am scratching my head on how to do this. I have a domain http://www.abc.com (for example) but my wordpress setup is on http://www.xyz.com. I want people to visit http://www.abc.com but have the wordpress from http://www.xyz.com serving this web address of http://www.abc.com. Both domains are separate to different hosting companies.

I am sure there must be a simple way of doing and I feared my mind just not seeing the trees cos of the wood.

Thanks
Tony