With AT&T and Verizon Wireless now both actively selling tiered data packages, some pundits think the days of flat-rate, unlimited Internet access plans are numbered.

Recent surveys show that while carriers are convinced the average consumer likes to choose between small, medium and large data caps, most consumers aren’t thrilled with the reality of having to track their data usage to be sure they don’t break the bank.

If you’re one of the growing number of Android owners saddled with tiered access, 3G Watchdog is your new best friend. Just install the app, and your incoming and outgoing traffic is monitored, down to the megabyte.

This free app’s best feature? As the month wears on and your online usage piles up, a colored icon in your notification bar changes from green to yellow to red. (Hint: Red means you’re nearly out of bandwidth!)

Comparing monthly usage numbers on your bill vs. the app might reveal some minor differences. It’s best to disable your access when you get close to your cut-off (within a few MBs).

Verizon customers might get slightly better data using the My Verizon app shipped with their device.