The guys at Skylab Mobilesystems have done it again: they keep creating these applications that I can't imagine living without. The latest is called Mobile Tracker and is described in their press release like this:
By taking advantage of the already built-in GPS receiver of the BlackBerry 8800 series, MobileTracker is able to record tracklogs. Those tracklogs are saved on the BlackBerry's internal micro SD-Card and can be viewed directly in Google Earth once you have the BlackBerry connected to your desktop and click on the tracklog file. To provide more flexibility it is possible to configure the delay between position recordings. So if you are on a ship crossing the Atlantic you can also set the delay to 5 minutes. MobileTracker works everywhere on the world, even without network coverage.
MobileTracker is available for $24.99.