Shoe-Goo works pretty well. I generally get a week or so worth of time (5-7 rides) before it rubs off. Make sure to clean the area with rubbing alcohol and let dry before applying. It's also better to use thin layers and build it up. Let each layer dry an hour or so and then let the whole thing dry overnight. If you just gob on the Goo in one go it will pop off the first time you push off from the pavement. I like to start the process after a few dozen rides, when the yellow sections are a little scuffed they hold onto the Shoe-Goo better than when they're new. Just make sure to clean them well.

Despite what the tech doc says, when the yellow areas are worn down the cleat is not necessarily worn out. It's more important to look at the section between the two yellow footies and make sure it's the proper thickeness as well as the contact face and make sure the divot created by the twisting motion is not too deep and allowing excessive rotation.

This is the area you really want to be concerned with:
http://www.slowtwitch.com/articles/i...leat_ledge.jpg

I generally get about 7k-9k miles out of my cleats but I occasionally do a lot of walking that creates more wear than the average road rider would encounter, I think.