Just over a year after the launch of the original iPhone, Apple has released the iPhone 3G in the United States and 20 other countries including Australia, Canada, Hong Kong, Germany, Japan, Mexico, the United Kingdom, and Finland. Apple later plans to unleash the iPhone 3G into another 49 countries.

In the U.S., the iPhone 3G is coming out in two flavors: an 8GB model priced at $199, and a 16GB flavor that costs $299. The former is available only in black, while Apple has released the latter with both black and white shells. Buyer beware, though: AT&T's cheapest iPhone 3G plan costs $69.99 a month with a two-year contract, and you'll want to cough up at least another $5 a month for a text plan. Those rates should make the iPhone 3G more expensive in the long run than its predecessor.Apple has opened its App Store to let iPhone 3G, iPhone, and iPod touch users download third-party software for the devices. The MobileMe synchronization service was also supposed to launch yesterday, but Apple says that's taking longer than expected.

Finally, Engadget reports that Apple has released 2.0 firmware for the original iPhone and iPod touch. The company charges iPod touch users $9.95 for the upgrade, but iPhone users should be able to grab the update through iTunes without paying anything.