Yes, several USB to Serial adapters will work. In fact I haven't found one yet that won't work. Note that there is no guarantee that all programs will work with all adapters. I've had very good luck with adapters using the FTDI chip set.
Yes the trendnet will work and so will the one that Hiegtx linked you to. Which ever one you choose make sure you download and install the latest drivers before you plug in the cable. I have used the trendnet without any issues at all.