Apple pushes OS X 10.5 to October. Students seeking the very latest operating system in September’s Back to School season will have to go with Vista.

The reason for the delay is iPhone taking precedence over the new version of Mac OS X. According to a statement from Apple. iPhone will require more development before it’s released. Apple has had to shuffle development and QA resources to meet the challenge of iPhone’s deadline.

Code named Leopard, OS X 10.5 was slated to be released at Apple’s World Developers Conference in June - but with a pending iPhone launch, the WDC deadline is just not going to happen. Instead, attendees of the World Developers Conference will be treated to a “near final version” of Leopard. A beta version of OS X 10.5 will also be available in June.

The good news for the Mac-faithful is iPhone is in no danger of release date tardiness. The company is striving to get everything in line for its consumer debut in June, and is expected to launch on time. The iPhone has already run a gamut of certification tests required of handheld telecommunication devices.

The new version of the Mac OS X is the sixth in a line whose pedigree dates back to 2001. The new version should be released in October, too late for Apple to catch the “back to school” market.

When Microsoft announced delays of Vista, it took its share of ribbing from the Apple nation. Here, MacNN provides reasons why Windows Vista delays will be good for the Mac OS. Of course it never occurred to MacNN that Leopard would also be delayed. Does anyone care to draw the conclusion that a Mac OS delay would be good for Microsoft? It’s probably not worth the effort.