http://www.ebuyer.com/product/104608 isn't bad and has a decent range so long as you can get the dongle in line of sight, I used a USB extension Cable.
Battery life isn't bad with light use my first set lasted well over 2 months, but then we had a change around and it took over the role as the main email, web and Office computer, the battery life dropped to about 2 weeks, but for light use and maybe a bit of email I would highly recommend it.