If insider sources prove to be right, both Fox and ABC have agreed to offer TV show rentals through Apple’s iTunes Store for US$0.99 an episode. Apparently both networks are planning to offer at least some of their program lineup, and Fox’s participation may be only on a trial basis, according to the Wall Street Journal.

Apple will be hosting a media event at 10AM pacific time Wednesday where the company is rumored to be introducing iTunes Store TV show rentals for under a dollar, along with an iPod touch update that includes a built-in digital camera.

Fox and its parent company, News Corp., were rumored to be on the fence over signing on with Apple’s TV show rental scheme as late as Tuesday afternoon. The apparent change of heart may have been a move on the part of News Corp. to push Apple into helping with its new digital-only news paper project and an iPad version of the Wall Street Journal.

While ABC and Fox look to be onboard, NBC Universal, Time Warner and CBS are most likely keeping their feet out of Apple’s TV show rental pool.

Be sure to check in with The Mac Observer for our Apple media event coverage later this morning.