Set up a Photobucket account.http://www.photobucket.com
Once that's done you can upload photo's from your PC , using the big blue link on the site.
You'll then begin to build a nice collection of pics and under them you'll get three boxes with link options.
Choose IMG Code (click left on you mouse to hi-light and right click 'copy')
You can then use you pics on forums by simply right click and 'paste'.
You can edit you pics on photobucket if they are too big. Go to 'edit' above your image.
Any problems, let us know.