I add an FTDI header in my projects as well for serial port debugging.
I have used FTDI Basic, FTDI Breakout Board with 6-pin adapter cable, this FTDI module from Mouser.com with 6-pin adapter cable
http://www.mouser.com/ProductDetail/mikroElektronika/MIKROE-483/?qs=%2Fha2pyFadugsEwyLV5fFyIWdPbushEDhRSvnBE0ODG8%3D
(at $11 I believe it is the least expensive FTDI module around outside of e-bay)
and also easy to build onto a board, like this protoboard
and CP2102 modules from e-bay with RESET trace to header cut and wired to DTR pin instead (needs different driver).