Telcel is now offering a contract-free version of the iPhone 3G in Mexico.
The cost of an 8GB iPhone is $7,899 MXN ($708 USD) while the 16GB sells for $9,199 MXN ($817 USD). Users who choose this option will be given $500 MXN ($45 USD) worth of talk time, and 30 days of unlimited 3G browsing.
In order to receive the talk you must use $100 MXN worth of talk time in a month after which your account will be credited with al $100 MXN renewable up to a total value of $500 MXN.
It is likely that Telcel has still locked the devices to their network so unfortunately this won't be easy access to an unlocked iPhone 3G.