" Logic '1' same as IR 'off' and logic '0' equal to IR 'on'"

Actually, simple IRDA-compatible seial links use short IR pulse = logic '1'; long IR pulse = logic '0' (or is it vice-versa?).
These are good for short-range, low speed links (19k2 baud or so).

Companies like Vishay and Agilent (nee HP) make simple encoder/decoder chips which simply sit between your UART and your IR transceiver; the FastChip library for the Triscend E5 includes an implementation for the configurable logic.

Maxim also have some Application Notes on the subject.

You could have found all this much sooner just by using the 'Search' button!
Why not try it now, and see all the stuff that's already here - probably including part numbers and links?!