I found this helpful so I thought I should pass it along. I painted our baseboards a couple of years ago. It was a pain in the neck. Think carefully before you take on this task!
I love their description. "Painting baseboards when you have wall to wall carpet is like trying to apply lipstick when you have a handlebar mustache. It can be messy, but with a little preparation the results can be quite stunning." It's true. I love the result, not the process.