I couldn't Bluetooth the software to my phone, no matter how I tried (the .jar file went across but not the .jad file), but with my Sony Ericsson, I managed to transfer the .jad and the .jar file on to the memory card via a card reader and install the software on the phone that way. I used the kaywa reader (http://reader.kaywa.com/) and made my own codes using their online facility (http://qrcode.kaywa.com/)
I think QR codes are going to be great on open day - if you provide the students with the phones/kit to read them, and then have a booth to help students get them on their own phones (which in the long run means you can use QR codes around the college more) - will try this out in Sept 08.
Agree with James re reducing the need to type out URLs etc on a phone to access a website, but I think simply using it for location-based information is useful, and if you provide students with the means to make their own for an exercise, it will get them more excited about preparing and then reading information then a simple label on an item/location.
Ideas: anatomy (qr codes on a mannequin/anatomical figure), parts of an engine, a nature trail - identifying plants, identifying health and safety signs around the college (provide a sheet of paper with the signs and the qr codes, they have to spot them around the college and fill in location) etc.