Paint Shop Pro (
www.jasc.com IIRC) do a 30-day trial but if you want something more permanent then you could try the GIMP...i don't think the Windows version is quite as powerful as the Linux one but it's still free i think.
http://www.gimp.org/ for general information and
http://www.gimp.org/~tml/gimp/win32/ for the windows site
but download it from
http://www2.arnes.si/~sopjsimo/gimp/faq.html to save you any compiling etc. Follow the instructions carefully, you can get the two files by clicking the "stable version" button on the left hand side.
If you want to save gif files then you might need to also get this file
http://www.iki.fi/tml/gimp/win32/gimp-gif-1.2.5.zip which you should extract to the plugins folder.
Hope that helps [img]smile.gif[/img]