That is because HP (Compaq), and Dell are big fans of the BCM43xx chipset which has long been a problem for Linux due to Broadcoms hostility to it.
But this has been solved in the kernel after the current one (.25) because the B43 driver now supports Rev 01 and Rev 02 chipsets without being buggy.
All you have to do is paste the firmware into the firmware folder, I presume for the next release Ubuntu will have a GUI clicky thing for this.
Unfortunately Hardy is the .24 kernel, but full support isn't far away :)
Written from a laptop with a BCM4312 Rev 02 on the .25 kernel
Not sure if Toshiba are a fan of Broadcom, but they probably are.