Debian (Squeeze) runs just fine on the Lenovo Ideapad S-10. Since Debian is careful about including only free software by default, you only have to enable the non-free archives to get the wireless card working after you are done installing! Everything else just works.
I'm a long time Debian user, so this page is brief and does not attempt to explain details about Debian. I'm also some sort of luddite since I don't use GNOME, KDE, and friends. I use xmonad as my window manager. So many of my notes below will be uninteresting to users of more "sophisticated" desktop suites, I suspect those would "Just Work."
For the record, I installed a OCZ Vertex 60GB SSD drive in my netbook. It works well, but the fan still turns on and so the netbook is not always as quiet as I'd like.
I installed Debian (Squeeze) before its final release using the Beta release of the installer. A 1GB USB stick (smaller ones will work), the installation manual (see the current version here), the "netinst" ISO image, a working ethernet connection, and a Linux machine to set up the USB stick where all I needed. As far as I know, the installer cannot use the Broadcom wireless card in the netbook for the installation because it needs proprietary firmware that Debian will not include by default.
When setting up the USB stick be sure all the files are completely and correctly downloaded. On my first attempt the vmlinuz file was incompletely downloaded, and it lead to a partial boot of the installer that confused me for a while! I did a bog standard guided install except for using ext4 (the default is ext3) as the filesystem.
I installed the acpi and pm-utils package. Suspend, hibernate, and suspend hybrid all work. The acpi command gives me the battery information I need. I also have acpitool installed. I have not yet figured out how to control the built in fan.
Add the non-free section to your /etc/apt/sources.list and install the firmware-brcm80211 package. Now reload the brcm80211 kernel module (or just reboot!) and you should see wlan0 available for setup.
I use the wpasupplicant package to manage my wireless connections. However, the kernel driver seems to have a bug where wpasupplicant (and perhaps other tools) seems to be unable to bring up a wireless connection after the laptop is resumed from a suspended state. The solution is to unload the module before the netbook goes to sleep, and load it on resume. Since I use pm-utils I achieve this by creating a single file which I arbitrarily called brcm80211:
shyamal@lambda:~$ cat /etc/pm/config.d/brcm80211 SUSPEND_MODULES=brcm80211
X11 works out of the box, without the /etc/X11/xorg.conf file. However, the touchpad on this netbooks is quite hopeless with this default configuration. I found a very useful blog which helped me tweak things. The first thing I noted was that with the default Debian configuration I get this error
shyamal@lambda:~$ grep ^\(EE\) /var/log/X11/Xorg.0.log (EE) SynPS/2 Synaptics TouchPad Unable to query/initialize Synaptics hardware. (EE) PreInit failed for input device "SynPS/2 Synaptics TouchPad"
With this default setup, tapping on the touchpad is never interpreted as a right click, and the touchpad is also abnormally sensitive to grazing by my fingers when I type. This is ridiculously disturbing, and the solution I've chosen is to run
shyamal@lambda:~$ synclient TapButton1=1 shyamal@lambda:~$ syndaemon -i 1 -d
after I start X (which I do with startx from a command line).
I don't really use the media functions of this netbook. However, the sound card works out of the box. I simply use alsamixer to control the outputs on the rare occasion I've needed to use it. I suspect desktop sound tools will just work (but I have not tried them). The video camera also seems to work fine: just running mplayer tv://0 will prove that.