Where to find code help and tutorials.

Hello,
I hope that this is in the right topic. I am running a network site and could use some help in developing it. I don’t want to know how to completely rewrite it just add a few things. Like on wordpress.com and blog.com they have featured blogs on the frontpage. I would like to accomplish this for my site and have random blog post from all blogs has well. Maybe add tags on the frontpage for easier navigation through all blogs. Has anyone integrated categories for blogs to be listed under?

Now just a few questions where I might find some css files. Where do I find the css markup for the registration and activiation. Any help would be appreciated.

[moved to Multisite forum]