It looks as though Apple has accidentally revealed an as-yet-unannounced feature coming to the iTunes Store, and it’s a big one, movie rentals. I’ve written in the past that I think this is exactly what iTunes needs to keep the iTunes video store on track (more so than ever now with the NBC departure), but also to finally make the AppleTV device make sense.

When you go to report a problem with the U.S. version of iTunes, you will notice now a whole slew of options for reporting problems for “RentalMovie”. It’ll be interesting to see if this slip up forces Apple’s hand and they make an announcement about the service soon, maybe at the Apple Expo in Paris at the end of the month.

It will also be interesting to see if these movie rentals continue to be in standard definition or if Apple will finally make the jump to Hi-Def. Microsoft has been offering high definition movie rentals over the Xbox Live service for months now, but Apple has resisted this move so far in both their movie and TV show downloads.

I think it’s a fair assessment that movie downloads and rentals haven’t had too much success in the online realm yet. There are quite a few services out there now, but none seem to be able to pull it all together and offer a package that consumers want. Some have good prices but too much DRM, some are okay on DRM but are expensive, some simply lack a good catalog, and some are very limited on the systems they will work on.

If there is one thing we know about Apple, they can make an online store work. Their iTunes Movie store has so far been hampered by a few things, namely its lack of studio support (aside from Disney which Steve Jobs happens to be the largest shareholder in). I also still believe Apple made an error in thinking that just like with music, everyone wants to own all of the movies they watch. Apple has always been big on the ownership idea (as opposed to subscription for iTunes Music), but with movie rentals, there are just so many crap movies out there that I may want to rent for one night for a couple of dollars, but would never throw down $10 for to own. iTunes Movie Rentals would solve that.

There is such a huge window right now for something like iTunes Movie Rentals because of the war between HD-DVD and Blu-ray, that appears headed nowhere fast except a stalemate. It could literally be years before either of these formats comes out victorious, and if that happens, look for movie downloads to take over the market before that. Apple has a shot to have the big piece of that pie, but that have to move quickly as other companies like Amazon and Blockbuster as coming along with full-court presses in this area as well.

When iTunes Movie Rentals service launches and becomes a hugh success (and I do mean when), the other studios will eventually fall in line to make money with iTunes. Apple simply hasn’t shown them enough yet for all of them to set aside their piracy worries and jump onboard (you’ll notice most of those that have aside from Disney, have only done so with their back catalog content). If movie rentals also launch AppleTV into a must-have device, you could very well see residual effects, like NBC limping back to the bandwagon. I know when movie rentals come to iTunes I will buy an AppleTV, but not before then.