There was some discussion before about this,and as the last person to try it found out you need a good front end reciever if you are going to get high baudrate.Depending on the range you want to transmit the data of course.
I have a ir reciever front end circuit which works well upto about 5 Mbit/second.I can send it you if you wish.I have also been playing around with rs232-irda converters and have been working on an irda protocol stack for a project i have been working on so I may well stick those on 8052 users page.