NewsForge has an article by James Glass (not his real name):
Imagine you want to create a user-moderated news service like digg.com that operates on SMS. On the neutral Internet, you rent a Web server ($7-$100 per month to start), register your name, and start programming. Total time required: less then two hours in most cases. But getting a service on the non-neutral US cell phone network would be a little different:
The first step would be to contact a company known as an aggregator. This company manages your relationships with the cell phone carriers — and that’s carriers, plural, because making an agreement with just one carrier ensures that your service will fail because it cannot effectively spread via word of mouth. The first requirement from an aggregator is a service charge, which starts at $1,000 per month. Then, you must buy a shortcode (which kind of serves as your Web site name) for an additional $500-$1,000 per month. But you’re not done.
The next step is satisfying the requirements of the cell phone companies. Many of these steps, such as requiring affirmative opt-in before a subscription can start, are not burdensome, and serve to protect the carriers’ customers. Others, however, border on ludicrous. Requirements vary by carrier, but some prohibit operators from offering games or sweepstakes, or require that subscription periods can only be monthly: not daily, weekly, or yearly. Others require that content, such as ringtones, be locked so users can’t forward them from their phones to their friends’ phones.