Spacetraveler, it would be better if you exported your user data to some open format (csv or xml) and then import the data to your site via PHP. Structure of data in Elgg is EAV. It's not relational database model, that's why it probably won't translate easily on to your site's database model.

We can create export script for you as a custom development for a reasonable price. If you're interrested, you can place the request via this page or to info@elggdev.com.

Thanks a lot guys. I still can't find it. All I see is a table called "Information_Schema". Where exactly is the elgg_users_entity table?

@Space..
I not notice your post before..
The solution is quite simple..
Send me a PM if interested or...
**    You are running Elgg on a Windows IIS etc Server, right ? (how the heck did i know ;-=)