My guess is: Ubuntu will be too slow (I've tried it on a simliar laptop). Xubuntu is no alternative either, just like Ubuntu, it's too bloated for older hardware. And Canonical's lightweight distro Lubuntu is nowhere near being installable at the moment.
Try a more lightweight distro light the Slackware based VectorLinux
(especially the light version is well suited for older laptops). I'm running VL Light 6.0 on a laptop with only 256 MB RAM and no problems whatsoever. My wifi stick worked from the beginning without any tweaks, just had to connect it.
Also, don't be afraid of Slackware-based distros. The times when they were newbie unfriendly are definitely over. VL Light comes with an easy installer and IceWM as default window manager, which is very intuitive and highly customizable. PLUS: VectorLinux has a great community
. You will likely be helped there within minutes...