Although rumors that Apple will include a third-party multitasking capability in the iPhone are as old as the hills themselves, a reference has emerged regarding a “multitasking dialog box” buried in the new iPhone OS SDK 3.2 beta 4 that apparently didn’t exist in iPhone OS 3.1.3.

Per 9 to 5 Mac, this could be the very first by-product of a new multitasking system for developers that’s being developed for the platform, presumably destined for an appearance in OS 4.0 when it’s introduced along with new hardware this summer. Still, it’s just as likely that Apple will continue to keep the iPhone’s multitasking capability to itself, a function it uses liberally among the phone and music apps, just to name a couple.

AppleInsider is currently citing a tipster claiming that Apple’s got a “full-on solution” to multitasking that would properly address its main concern (battery life issues) for release this year.

Stay tuned for additional details as they become available.