That looks like a text effect from Invision, though I'm sure it's been done other places as well. Basically, you're just using background colors and other characters that have the same color as the background to create the colored areas.
Basically, something like:
* I can't seem to paste Ctrl-K... there should be a Ctrl-K before each set of colors. There should also be a Ctrl-O at the end so you can have a space after the word. Note that if you copy/paste this into mIRC, the control codes will be there even though they aren't showing here. Any maybe depending on your browser/etc, you might see them here even though I don't.
//say 04,04 Hello
//say 04,04 01,04Hello
//say 04,04 Hello
That gives you a red box with black text in the middle. To do the shadow, you do the same thing, but add additional colors. The reason I have the same word in the top and bottom rows is to guarantee that the width of the box remains the same on all 3 lines regardless of the user's font. Note that you might also want to consider using bold text to make it stand out better. Just remember to bold all 3 lines.
