Creating good icons isn't easy, but can be a lot of fun when you get the hang of it.
It requires a lot of practice and time to get your own method and style.
I use microangelo http://www.impactsoft.com/ for the majority of my work, and then sometimes Icon Collector Graphics Editor http://www.greatowl.com/ or PhotoShop for any extra colour alterations and tweaking.
Generally stick to a certain style or theme, if your doing a system 'set' or theme.
If you want to add an extra level of 3D'ness to them... make sure you get your lighting right, you generally want lighter colours in the top left, and darker colours and shadows in the bottom right, if your going for the 'traditional' 3d look that is.
Check out: http://w1.864.telia.com/~u86404543/cci/iconlinks.html and http://www.iconparade.com/ for a massive list of great icon sites... have a good look around, get inspired and get pixel pushing.
There really aren't that many icon-making tutorials out there, but here are two of the main ones (for mac, but the concepts are the same):
http://www.tcp-ip.or.jp/~s-iga/tips/tips&tricks.html
http://www.iconfactory.com/howto_home.asp
They teach the basics... so you can take it from there and develop a style of your own.
Good luck.
