I tiled a whole bathroom in very hard porcelain tiles using an Exakt saw
(purple version) and diamond blade:

http://www.fredshed.co.uk/exaktprecisionsaw.htm

(DIY version also on Amazon).

I found the best technique with straight cuts was to saw a groove about
half way through the thickness of the tile and then snap. For more
complex cuts, saw as deep as the tool will go and then nibble with pincers.

This tool is also great for laminate flooring. I've also used it to cut
down a stainless steel splashback. When cutting thin sheet metal, it
doesn't distort the edge like a jigsaw does.

There are a few downsides, but I don't believe they detract seriously
from the usefulness of this tool:

1. It's awkward making blind cuts as you can't see the blade and have to
rely on a scale on the side of the tool.

2. The max. depth of cut is limited to around 14 mm (less for the DIY
version).

3. You must use vacuum extraction (but a hose is supplied to connect to
a domestic vacuum cleaner).

Hope this helps,

Roger.