If you are thinking about buying a MacBook Pro, the tea leaves suggest that you might want to wait before you pull out your wallet.
MacRumors points out that Amazon is currently showing long wait times before some of the MacBook Pro models ship. They add that they've heard from others that supplies are running low.
Given the revision history of the MacBook Pro line, it would not be surprising to see a new version in the near future -- in fact, it would be surprising not to see an update soon. The real questions are: 1) when? and 2) what new features will they include?
One potential new feature might be the Sandy Bridge processors and possibly some solid-state drives like we've seen in the MacBook Air, although I would still expect that most of them would come with regular hard drives for the time being. Another lingering question is how long Apple will continue to include optical drives in its computers. Although it seems like it would be "too soon" to drop them entirely, I still remember when Apple dropped the floppy drive long before most people thought they were dead.
I'm not a huge fan of trying to guess when Apple will or won't release new hardware. It's been fairly predictable with new iPhones in the summer and new iPods in September, but release cycles for other products aren't nearly as reliable. Given that Apple's own online stores show plenty of immediate inventory, we could be looking at another month or two before the new versions ship, or we could wake up next Tuesday and find the store has gone down overnight and come back up with new versions.
That said, unless your current MacBook Pro was lost, stolen or caught on fire, I'd recommend being as patient as possible.