One way I didn't mention to "find" (i.e. take without permission) images on webpages is to look through the source.  Checking DOJO of PAIN's source I found:
http://www.dojoofpain.com/redsteel/images/header.gif

That was exactly what I was looking for and will be a great image to use for this tutorial on MS Paint.  So, if you want to follow along save the above image like I showed you in Training 1.0.

Since I want this to be a sig banner 375 x 75 for Red Steel I have several things I need to resize the image, but before that I'd like to remove the DOJO of PAIN text.  To make sure I remove all of the text and nothing more I'm going to zoom in on that area.  "View > Zoom > Custom..."
http://kontek.net/Luigison/dojotraining/customsize.PNG

Pick a percent and see what the text we will be removing looks like at your computers resolution.  Change to another percent if need.  Once you have a zoom level that you are comfortable with we'll start to remove the text from the image.  Select the "Pick Color" eyedropper from the tools on the left.  With the eyedropper click somewhere in the solid background color around the text.    
http://kontek.net/Luigison/dojotraining/eyedrop.PNG

Now that you have the color to paint over the text you need to select the paint "Brush" tool from the left and choice an appropriate sized brush from the lower left of the tools section.
http://kontek.net/Luigison/dojotraining/brush.PNG

Now click the left-mouse button while over the text you want painted over.  You can click for each section you want painted or click and drag to make brush strokes.  If you mess up the from the menu use "Edit > Undo", but be warned that MS Paint does not store many undo or have a step backward function.  
http://kontek.net/Luigison/dojotraining/undo.PNG

Now let's see what it looks like normally.  "View > Zoom > Normal Size".  Looks good, but it's still too big to for a signature.  To see how big it actually is from the menu "Image > Attributes".  Note that the image is 800 x 215.
http://kontek.net/Luigison/dojotraining/attributes.PNG

Do not change the size from the Attributes popup.  If you did it would simply cut the image off.  We just need to see the size here to know how much to change the size.  Unfortunatly most version of MS Paint do not allow you to pick an actual size to change to directly.  Instead the image is changed by percent so we'll have to either make a calculation or do some trial and error.  "Image > Stretch/Skew".
http://kontek.net/Luigison/dojotraining/stretch.PNG

First of all note that there is no link or lock holding the horizontal(width) and vertical(height) together so to shrink the image without distorting it you should use the same percent for each.  Disregard the Skew section for now.

Now for some math.  Since the image is 800 x 215 and we want it to be 375 x 75 which is not a perfect ratio we should shrink to the width then ajust the height.
http://kontek.net/Luigison/dojotraining/calc.PNG

So, let's change both the horizontal and the vertical to 47% and press okay.  Notice that the background is pixalated.  Thus is the way of MS Paint.  Doing this same thing in Photoshop looks much better.  Now, check the size now with "Image > Attributes" and you'll see that the image is now 376 x 102.  So change those nubmbers to 375 x 75 and click OK.

This looks pretty good.  I like the little girl with the katana on the left and the guy with the gun on the right, but the piece of the girl with the gun in the middle just don't work so go delete them like we did the DOJO of PAIN text earlier.  Since MS Paint pixelated the background you probably want make the area you painted over look the same by adding in some of pixels with the "Pencil" tool.

Same the image, but be careful because MS Paint will not let you go back to the way it looked before you saved.  It's actually a pretty good idea to press your print screen button so that you can past it back if saving messes up the image.

Here's a banner that looked perfect before I accidently saved it as a JPEG with MS Paint:
http://kontek.net/Luigison/dojotraining/weopon.JPG

Here's the results from this MS Paint tutorial compared with the same thing from Photoshop:

MS Paint:
http://kontek.net/Luigison/dojotraining/header2.GIF

Photoshop:
http://kontek.net/Luigison/dojotraining/header.gif

As you can tell Photoshop is clearly the better program, but considering it's price and the fact that most Windows computers come with MS Paint it may not be worth it to you to buy Photoshop.  You might want to consider download a free copy of GIMP http://www.gimp.org/ though.  If people wnat I might do a Gimp tutorial too.

My tutorials:

Luigison's Training 1.0: Finding & Capturing Images http://www.dojoofpain.com/redsteel/forums.html?view=posts&forum_id=234&topic_id=43139
Luigison's Training 2.0:  Photoshop Magic Wand & Resizing http://www.dojoofpain.com/redsteel/forums.html?view=posts&forum_id=234&post_id=44880#post_44880
Luigison's Training 3.0: MS Paint Image Editing 
Luigison's Training 4.0: Links, Clicks, & HTML (coming soon)

If there are any other tutorials you'd like please let me know.

If you found this tutorial useful please click the http://www.kontek.net/Luigison/dojotraining/plus1.png at the bottom right of this post.  If you didn't like or had problems with this post please reply, PM, or otherwise contact me before giving me negative feedback.  Thanks.