I can't see very clearly, but it looks like the contacts on the old usb port were damaged when it came off, so if you are going to try and repair it it is probably best to buy a new one. It is quite possible to solder a new one on, but quite a delicate operation due to the small size of the circuit board traces and contacts and if you are not careful the heat from the soldering iron can bring the circuit traces off the circuit board, which incidentally is what happened when I tried (and failed) to perform a similar operation of reattaching a mini USB port back to a cheap digital photo keyring. So in short, it is possible, but depends on your soldering skill. Fortunately, I haven't needed to try this on my N900, but should I ever have to, I'd probably invest in a decent soldering iron to do it since I've only got a cheap one at the moment.