If you follow Cheryl Johnson or Kristal Kraft(whenever she writes here again...KK did your google alert go off yet?), you have seen the uses of Screen Capture or Screen Prints.  They usually use Snagit.  Everyone using a PC with windows has a screen capture program built-in.  (MAC Users I am sure have something more elaborate than this...write your own post Turner!!! :-)) The "Prnt Scrn" button will work for you.  By pushing that button you now have captured a copy of the whole screen.  You can paste that into any MS program like Word or Publisher, etc.  If you need to doctor it up, you can paste into  Paint to modify it.  (Crop and write text on it)  Save it and use it in any program as a picture.  Let say you don't want the whole screen but only one window.  Click on the window to activate it and Push ALT+Prnt Scrn and this will only copy the active window not the whole screen (providing the active window isn't the whole screen)

If you read my post before, you know I like FREE.  Especially Free Software.  I usually get it at the Give-Away-Of-The-Day (today is a Photo to Film Software)  I picked up along the way a program called TNT Screen capture.  I used it to capture the finger on the keyboard and the Snag It picture.  It has built in feature like the Print Screen but you can also adjust what you what you really want instead of the whole screen.  It will also add nifty little features like torn corners or rounded, shadows, etc.  You can add pictures and arrows to this also right in the program and save it for use in a blog post or marketing material to show off a feature of your website. 

Since I have become addicted to Flickr, I have found another FREE program offered by them called Flickr and Webimager.  It is not as fancy as the other two, but you don't have to send to another program to crop it.  It will let you take what you want.  You can save directly to your harddrive or straight to your Flickr Account.  They have plenty of third party software for you to manage your photos. 

Short and sweet...Just a couple of programs to help you get your point across with illustrations.