Can I re-partition my harddrive?

Hi all,

I'm just trying to get my head around setting up Windows 7 on my Mac with boot camp. I'm actually having the same problem downloading the windows support software through the boot camp setup assistant that a lot of people here seem to be having, but that's for another discussion...

For the moment my question is this: Say if I partition my harddrive for windows use, and then later on I realise I want more space on the harddrive designated for windows (or indeed less), is it possible to re-partition the hard drive? Or is it the case that if I partition it and give windows X gb, I am stuck with that and cannot change it?

Thanks in advance.