Apple is reportedly shopping around a subscription service to TV networks that would give iTunes users a catch-all subscription for $30 a month.

According to multiple sources speaking to All Things Digital’s Peter Kafka, Apple officials have been proposing the idea to network executives over the past few weeks.

The subscription service will be monthly and will allow viewers to see TV programs via iTunes on an on-demand basis.

Disney is one of the companies being courted. Apple's CEO, Steve Jobs is the largest single Disney shareholder, which could facilitate a deal like this going through.

If Apple's service is approved, its entry to on-demand-viewing could rival what viewers not get on cable TV.

There are currently over 65 million people with iTunes accounts. An audience of that size could be very attractive to networks as they are already challenged by the growing number of viewers prefer to view content online for free on Google's YouTube and Hulu.

The sources said Apple wants to roll out the service early next year.

Interestingly enough, Piper Jaffray senior analyst Gene Munster predicted earlier in August that Apple might do something like this, though he predicted 2011 as the launch year.

Apple’s proposed launch timeframe for the new service is early 2010, but that’ll be a tall order given the current state of buy-in from content providers.