With Photoshop there is a utility called magic lasso, it works well there is also just a plain Lasso tool that you have to use your mouse to draw around the object you wish to save, since Adobe has released Photoshop CS5 which is about 1,100.00 you can pick up some of the earlier packages (legal ones) CS 4 for under 500.00 or going way back Photoshop 7 for around 50.00 the learning curve with Photoshop is pretty steep, if you really want to learn the complete use of the software.
If you have any students around, you can get an Educational release for quite a bit less. OR download Gimp Photo editor, it will do nearly every thing that Photoshop will and it's open source so it's free, it was designed to be used with Linux, but now it's cross platform, and on par with Adobe Photoshop CS7. Don't confuse the CS series with the regular version 7 there is a 6 0r 7 year and a world of difference, but since the learning curves are about the same and there about an 800.00 price difference I'd opt for Gimp. I have CS4 at home but I have Gimp at the shop. Adobe is mean about their licensing. No way I'd want to use a bootleg copy.