WordPress MU

Hello all,
I currently have 150 WP sites that I'd love to all have under the MU "umbrella." (These are all my sites...niche sites for our region. A great idea with unbelieveable managerial issues! LOL)
I have looked and read in this forum that we can have top level domain names show (www.domain1.com, http://www.domain2.com etc...). Great.
However my issue some of the sites are version 1.5, others 2.0.1 and some are the latest version of WP.
I recall DrMike (or someone) stating that you can "convert" them in the CP, which probably works with the latest sites...however do I need to go thru all the sites and update the version of WP BEFORE I can switch them over?
I have not done the WPMU install YET so also any suggestions on things to avoid or watch out for to set up this monster??
MU seems to be a definite answer to manage an incredibly unmanageable situation. I apperciate your input and will keep reading the forum too uncover more info/advice.

Upgrade all to latest version of WP. (Yes, you need to.)

Export each site, then import into MU.

It won't be "perfect", but it won't be too far off.

Advice: know what you're getting into. MU is server software, and requires an advanced knowledge of not only how WP itself works, but apache, mysql, and php as well.

Also, as a note, it doesn't like a shared hosting environment for more than a handful of sites.

Thanks for the info.
You say that MU "doesn't like a shared hosting environment for more than a handful of sites." We have a dedicated server with 14 IP addresses...will that make a difference or is it more the technological restraints of the software?
Would installing more than one copy of MU be helpful?

MU needs resources to run efficiently. In a "shared" environment with several (~100 or so) blogs, MU needs more than what most shared hosts consider as their "fair share" so to speak.

Since you're not allowing additional registrations, or so it would seem, you should be fine on your box. Depending how much other stuff is on it, etc.

Multiple installs wouldn't really make sense.

I have a somewhat related question. I have two Mu installations and I'm about to dump one of them, but I want to save a few of the individual blogs and move them into the surviving install. Is there an export feature in Mu to make that move easier? I can't seem to find it, and searching the forums only turns up posts about going from regular WP to Mu.

from the blog... manage -> export

*sigh* You know it's funny, I sit in front of a computer all day as a sys admin managing a server farm with 3000+ machines with no problem, but when I come home to mess with my blogs I turn into and idiot that can't even navigate the menu.

I appreciate your patience with me thus far.

It seems that when you import the posts you will want to be logged in as the owner of that blog, otherwise the posts will be tagged with you as the author.

Other than that one oops, very smooth.