ir stands for Infra-red. you need to haf an infra-red receiver in the computer. most laptops haf it built in. in case of desktop, get a usb IR dongle (thats the cheapest solution rather than getting the IR header for your motherboard). no you need not change the motherboard. just get this dongle for about INR 400 or so.
if ur phone supports native ir transfer then you can simply find out where the ir port of the phone is and point it to the the ir dongle. if u use windows then make sure you enable the infra-red service from admin tools>services> ir service. if you use linux start the ir service.
if in windows, and ir is natively supported by phone just arrange phone and dongle in line of sight and voila! windows (2k,xp) will detect the phone. simply right click on images or audio files supported by ur phone and select send to>a nearby computer. the phone will ask for transfer confirmation. answer affirmative on phone and hey presto! theres ur image/audio on ur phone!