I love taking self-portraits (just look at my avatar

) and always found the focusing to be the worst part. So I got on amazon and purchased an off-brand remote control for my camera which made self portraits and family shots so much better.
The remote allows you to use autofocus which is more reliable than guessing. No, you're not going to get locked on focus on the eyes unless you position yourself exactly right but you can just have a big depth of field by keeping the aperture small which will give you more to work with. If anything, just do some sharpening and masking to get the eyes sharper than the face.
Tip:If you're going to take a self-portrait with you to the side of the image, just set the focus point on the camera before you get in position.
The remote I bought was [ame="http://www.amazon.com/Opteka-RC-4-Wireless-Control-Replacement/dp/B0019RGQVU/ref=sr_1_1?ie=UTF8&s=electronics&qid=1269373702&sr=8-1"]Amazon.com: Opteka RC-4 Wireless Remote Control for Canon EOS Digital Rebel XT, XTi, XSi, T1i, T2i, 7D & 5D Mark II Digital SLR Cameras (Canon RC-1 Replacement): Electronics[/ame]
There are better ones but that one worked fine for me.