Yeah, I used an IR adapter that connected via my serial port... I found it very useful for sending files to my girlfriend's laptop, even large files! Unfortunately you are limited to the serial port's 115K throughput limit, but then again, it ooks like the USB adapter you are looking at has the same limit - must be an IRdA spec thing.
Anyway, you can use the IRdA for connecting to a laptop (like I did) since most laptops have built-in IRdA ports. You can also use IRdA in place of a docking ststion for stuff like iPaqs, etc. A very useful addition to the desktop, IMHO!!
mavis