Cari, the good carpet cleaning services around here have pros at this. The kind of places range from the Stanley Steamer to the oriental rug specialists. I can't tell you much more, but you might search the bigger cities near you for places that say they do dying. You can do this from a web site like yahoo.com or switchboard.com without even putting in anything other than your location. They will sort by business type and distance from yours. Look for "carpet cleaners" and call the ones that look like possibles about their dying capabilities.
Imogene doesn't have a bad idea but that could turn into a bit of a mess if someone spilled anything with alcohol in it on the marker. Depends on how big a problem you have and what an honest guess about future problems would be.