You can use Adobe Photoshop Elements 3, which is a toned down version of Photoshop.This is good for amateur photographers, digital imaging enthusiasts.
*www.adobe.com/products/photoshopelwin/main.html
If u want it higly professional,then go for Adobe Photoshop CS,but learning curve is steep.
*www.adobe.com/products/photoshop/main.html
If u want ease of use,go for Ulead Photo Express,it has some nice features and very easy to use.
*www.ulead.com/pe/runme.htm
One software which is capable of competing with Photoshop is CorelDraw Suite (my fav!!) ,which has PhotoPaint for photo editing.
*www.corel.com/servlet/Satellite?pagename=Corel2/Products/Home&pid=1047022690654