I use Ubuntu and it does have KDE applications available.
I think I'm safe in saying that all or most the below will apply to Kubuntu as well or be very similar.
Be prepared for a fairly steep learning curve to get the feel of the "command line" and Unix style operation if you have not experienced it before.
Cool though and worth it especially since it's FREE!
Getting it to connect to the internet was my first big difficulty and took me a couple days.
There is a REALLY fabulous forum community
http://ubuntuforums.org/forumdisplay.php?f=331 (General Help)
where they will usually answer your question in a couple minutes and work with you. They also answer Kubuntu questions.
When first installing, download to your computer from http://www.ubuntu.com/ then make an "image" to CD and it will allow you to install as dual boot or to create a partition. For starters, you might want to stick with the easy install because it's less complicated.
You might have to reboot back and forth in the beginning asking questions until you finally get internet access after which, you can ask from within ubuntu with a regular browser (Firefox).
You CAN access your other operating system files from within Ubuntu very easily from the main file system which is very helpful. I forget right now but I think the directory is called "Host".
If you're connecting into wireless internet access you might have to install a NDIS Wrapper and it gets pretty confusing but keep trying. Pretty cool once it's all going.
These are just a few things I wish I had known about in the beginning having started from nothing.
Go for it and enjoy!