Designing Kitchens and Bathrooms - Making a hole in porcelain tile

I'm tiling the walls of my bathroom and need to cut several holes for the different pipes to come out (shower head, handles, sink, outlets). I've tried
using a carbide drill bit but it took about 1 hour to penetrate 1/4 inch. Are there any special drill bits
or tools for this job? Would one of those high speed
cutting tools like Dremel work?
Again, the tile I'm using is 12X12 porcelain.

thanks,
Luis

cut them before putting them up - use diamond masons blade/grinder

:) The use of a Dremil Tile cutter is an ok option however it takes
alot of practice to get it right. Most Tile centers have a hole saw
that require a spade pilot bit to mark center of hole than you can
use the hole saw to cut through the tile with ease. The most
common mistake I have made is trying to skip the pilot hole step.
The hole saw has bits of diamond attached to the body and is
only for use on tile. Good luck, and please let us know how it turns out.;)

Thanks for your advise. Most tile places that I've gone to say they have carbide hole saws. I tried
using one but, as I said before, was unlucky and
it took forever to penetrate. One place told me
to try to find the diamond hole saws, however,
when I got a quote for about $100 for a 1 3/8' hole
saw, I decided to try a high speed rotary tool.
The bit I'm using is still carbide but it does make
the hole faster than my drill. The only problem is
that the bit seems to become dull after a little while.
It's, however, cheaper than the diamond hole saws
(about $6 per bit) and I can do rectangular cuts
for the electrical outlets. Thanks again.

Luis