Lots of marketers and journalists are writing about the use of the phone as the hot new marketing machine. Apple’s iPhone release hasn’t done anything but flame this hot fire either.

The truth is that for most the phone as a marketing medium still only represents possibility, but there are some fun and interesting plays being built around this that may be worth a look for the right business.

The most common growing use is in the are of text messages (SMS). So far, this has been primarily an email replacement for opt-in parties. This should continue to expand.

Here are a couple idea starters for some new categories ripe for phone applications.

Advertised text messaging on demand – Reactee – Create a T-shirt with a text message – Viewers see the shirt text a short message to 41411 and get a more detailed text message back in return. This could be a great play for events, non-profits and political causes. Try it – text ducttape to 41411.

GPS or category coupon delivery – Cellfire sends coupons for pizza, flowers, and movies to mobile users who redeem them at the store by using their phone. The coupons are stored on the phone.

Free information services – Free directory assistance from Goog411 – To try this service, just dial 1-800-GOOG-411 (1-800-466-4411) from any phone. You can search by name or even category and have the contact details sent to your phone while you are connected – all for free.

For the moment, one thing looks pretty clear, the standard interruption advertising methods (now almost becoming lumped with spam) won’t cut it here. Traditional CPM ads don’t seem to make sense either. What does look like it will gain traction is service replacement models that are ways for users to give permission to advertisers who are willing to give or takeaway something that was a cost and turn it into an ad supported freebie, much like the 411Info model.

It will be interesting to see how this space evolves over the next few years.