3.5 http://www.microsoft.com/downloads/e...displaylang=en
3.5 SP1 http://www.microsoft.com/downloads/e...9-81da479ab0d7 -VERY IMPORTANT ONE!
4.0 http://www.microsoft.com/downloads/e...displaylang=en -NECESSARY FOR 2.23 and newer
4.0 standalone installer http://www.microsoft.com/download/en....aspx?id=17718
We'll soon be going to net framework 4.0 standards so if you haven't already you might want to get all of these installed(especially if you are running win xp) so you are a step ahead of the game once the next public software is released