My hosting company stats the following:

Ensure all your domains are pointing to the root (/.) and you are redirecting them to different folders using a default.asp script.

Is anyone familiar with this type of setup?  I'm a first time installer and waiting until next week for 4.5 to install.  Also is there a test page or file that can be used to run on the server to ensure that all the requirements are being met for installation.

One more quick question, I always seen SQL 2005, but my hosting company uses mySQL, will that work?

crap, but DNN is a multi portal app right, cause I have like 5 domains, 3 of which would be using it if I got it up and running, would hate to have to move all of my domains, really gotta rethink this whole thing now...

so if I got it hosted somewhere else, would I be able to have multiple site from that one location?

also, if you know any reputable companies for hosting it would be appreciated.

The difference is probably in the hardware mixed with the load it is put under.  To get a profit the cheaper plans probably have a lot more sites running on the hardware. So each site has to share the available resources.  If you get a lot of busy sites on the one server then the response for each is going to slow down.
Another thing to consider is actually how much space you need.  2GB is probably more than enough for most small business sites.
It all comes back to you get what you pay for.
HTH
Antony