This definitely isn't easy if you are new to linux. Documentation is very patchy.

the easiest way to get started is to use the vmware appliance:

http://maemovmware.garage.maemo.org/

it is a customized xubuntu that includes the maemo SDK (for both OS2007 and OS2008) and eclipse IDE integration. I had troubles with network configuration in scratchbox and had to adjust some network settings.

Then you want to go through the Training manuals and tutorials at maemo.org, see:
http://maemo.org/development/training/
and
http://maemo.org/development/documen..._tutorial.html

The maemo platform is very C-centric though there are bindings for C++, Python and maybe others. If you want to ease your way into development you might want to start with some python hacking. You can develop python apps right in the device using pygtkeditor. A good maemo python tutorial:
http://pymaemo.garage.maemo.org/docu...emo_howto.html