Our bathroom counter top is in perfect shape, but is outdated and ugly. Any hints about tiling over it? It has no curved edges, is firmly achhored to it's substratum, and I, of cvourse, smooth.

How are your sinks installed?

You could sand it and then apply your tile with modified thinset. Edging could be done with bullnose, or wood, or metal tile edging if the tile has no bullnose available. Here's an example of Schluter Rondec CT metal edging in brushed satin nickel

http://i2.photobucket.com/albums/y3/bljack/edgetrim.jpg

I have tiled over formica. First sand it with coarse sandpaper and then prime with an oil-based primer. When that dries you are ready to tile. I would use ceramic tile since its easier to cut.