There are different formats of I2C addresses - 7 or 8 bits. Arduino uses the 7-bit format, so to convert an 8-bit address to 7-bits, you just shift it right by one. That's how the 0x02 8-bit address is converted to the 0x01 7-bit address.
Source: http://arduino.cc/en/reference/wire
"Note: There are both 7- and 8-bit versions of I2C addresses. 7 bits identify the device, and the eighth bit determines if it's being written to or read from. The Wire library uses 7 bit addresses throughout. If you have a datasheet or sample code that uses 8 bit address, you'll want to drop the low bit (i.e. shift the value one bit to the right), yielding an address between 0 and 127."