i heard marshal was comming out with a gps tracker

The system is still in "beta" and being tested daily, and subject to change prior to public release later this year.

A few things have to fall in place before the release, one of which is a new battery that is being developed. Battery life is expected to be in the 7+ day range, with continuous use. It might be longer depending on the battery being developed.

Garmin has ~50 different frequencies in use for all collars, Marshall will have 5000

It will be a handheld GPS used in conjunction with a traditional radio system. The collars will be the same size as the Marshall radio collars, but they will be a dual collar. If you lose GPS function, you can still track to them with the Marshall system.

Expect a release sometime late 2010.

You will be able to see your dogs and their relative distance on the GPS handheld similar to the Garmin.