I had come across this service some time ago but can't seem to find it again.

It is a company that has paid models that you can choose from. You give them a script and they record themselves.

It's a flash animation that is incorporated into your site but it gives the illusion of a woman walking onto your screen to introduce your product/service.

Anyone know what Im talking about?

Thanks~

I think I've seen it before. But the trend has gone away from overlay ads that cover content - it pissed off the site visitors.

Maybe that's why I can't find them anymore...

It would have worked great for my new little side-job site.. but oh well. Thanks NK

There's several of them that I have URLs for: SitePal, and Voki, Website Talking Heads, and Media Semantics. That should get you started. :)

Well, I think you want to find some service like website talking character. I found some providers:
online video spokesperson - online presenters - avatars flash animations website person | yaoti ®
AvaGuide - Video Talking Characters for Web
Talking Avatar Demo - How To Make Speaking Characters

It provides some way to make your website more animated. So does some demo creation software:
Samples of video from screen, make software demo by screen capturing software