WordPress MU

I currently have four blogs running four separate installations fo Wordpress. I wanted to switch to MU so there is just one set of user registration database across all the four websites. On top of that, I also have a vBulletin forum that has a separate user base.

First, is it worth switching to MU considering that its being integrated with Wordpress? Secondly, can someone help me with the project?

"First, is it worth switching to MU considering that its being integrated with Wordpress? "

Yes, considering that when it IS integrated you can do the same thing. you can just do it now or later. You pick. Either way, you'll have to do integration to get all four blogs running off one install.

Here's a link to get you started:
http://bavatuesdays.com/importing-a-single-wp-blog-to-a-wpmu-installation/

If you wait until after the merge, you can just start from one of your installs and merge the other 3 into it.

What are the benefits in this integration project?

Integrating WordPress and WordPress MU? There are a number of benefits, chief among them Donncha won't be the sole developer as he is right now with MU. Security updates made for WordPress won't need to be merged and updated to be applied to MU.

The list goes on.

What are the benefits in this integration project?

Its been explained - one code base for developers to maintain. For end users it means having to only maintain one installation.