I have personally had the best luck with PC-BSD
for an install. I'm typing this from a Dell Inspiron 1501, but I have not actually tried a *BSD on it. However, you should be able to get help from the Dell page on TuxMobil
... similar laptops with *BSD or maybe some of the many Linux tutorials for the 1501 (I wrote one) can help you out.
If you are just looking for a live CD to try and don't necessarily want to install BSD (though I guess that's pretty much pointless, but you can try!), there is Ging
, which is based off of Debian/kFreeBSD
. It is slightly dated (KDE 3.4) but I just booted it up Sunday or Monday to play with it, so I know it works.