Maemo is the open development platform for applications and technology innovation for handheld devices used in the Nokia 770 Internet Tablet. It will also run on other maemo compliant handheld devices in the future (FWIW). It was developed by Nokia as opensource and offered to the community. It brings to developers a development environment and optimized user interface customized for handheld screen size and usage.
 Maemo is Gnome-like and Mainstream
Some decisions made during development of the 770 are today reflected in maemo. Most noteworthy is the use of GNOME as the base for the device user interface. The user interface is enhanced and combined with Nokia's long-term experience with end user user interface interaction and interface design. Currently maemo is developed for the Nokia 770 Internet Tablet. Future maemo releases will be developed independent from particular device hardware. Nokia has recently higered several developers to improve maemo and make it device-independant.
The framework is based on basic GNOME technologies like GTK+ widgets, theming engine, Pango for localization and multi lingual, input method framework, Gconf configuration system and gnome VFS. Maemo uses the Matchbox window manager as it is more suitable for handhelds than regular Linux desktop environments. Multimedia is based around Gstreamer, Helix and EsoundD.
The core non-UI is composed of the mainstream open source components like glibc, bluez bluetooth stack, standard Linux networking (ppp, autoip, openobex, iptables, wlan etc), Xserver, expat XML parser, D-BUS to name a few. Some of the components have been modified to meet the resource constraints of a handheld device.
 Maemo is light
Maemo runs on ARM or x86 CPUs in a minimum 32Mbytes ROM and 64MBytes RAM. Maemo ditches bonobo to lose weight. It is not hard to get started using Maemo (or so they claim).
 Development platform for OLPC
Perhaps Maemo on the 770 could also be used as a development testing platform for OLPC Python Environment similar to a Zaurus. Couple a 770/Maemo system with a Freecharge portable charger and you will feel the same pain as the kid with the OLPC.
Developers can get olpc boards now via the Developers Program also see Notes on using the OLPC developer boards. The software from Maemo could be useful to the sugar project (see Sugar and Maemo). I don't think that the 770 is better the a real hardware olpc board.