I just reactivated an old laptop, HP Omnibook 4150 Pentium 2 366MHz 128MB RAM, and installed the very light version of Linux, the Puppy Linux. I made a new partition schema, 4 GB for ext2 - 1GB for FAT32 just in case I'll need it - 1GB linux swap. I used a live CD in order to install it; during the installation I decided to let the installer.
I just had to fight a bit against the sound card, which is actually a CS4232; I modified the etc/modprobe.conf as following:
options snd-cs4232 port=0x534 cport=0x538 mpu_port=-1 fm_port=0x388 irq=5 dma1=1 dma2=0 isapnp=0
For the rest, graphic card, wireless card (a pcmcia belkin), keyboard, usb port, CD, everything went flawless.
A great distribution, very very light, running completely in RAM; the performance of the old Pentium are stunning, comparable with the other PCs I run. Web Radio, actually the reason why I started, is perfect. Youtube or video with complex codec are quite jerkily. Quite curious is the fact that the live version on a CD is somehow faster than the one I installed on the hard disk.
However a very good distribution. Consider it, and consider that an appropriate hardware can be found in ebay for just some Euros.