coloring ceremic tiles?

If the tiles have any glazing, you can't "stain" or paint them . And I doubt you would have floor tiles in a bathroom that are porous.

How about a nice indoor-outdoor carpet ?

otherwise smash them out and replace.

AMUN

Tile refinishing is a job for professionals.

However, even those process, I don't believe are durable enough for floor use to withstand the foot traffic.

Have a look here though

Search the newsgroup archives (groups.google.com) and see how many folks have made the mistake of just trying to paint tile, and how helpless the situation is once the paint starts peeling. :-)

-- Todd H.