<p>I was always attracted to the world of kernel hacking and embedded systems.<br>
Has anyone got good tutorials (+easily available hardware) on starting to mess with such stuff?<br>
Something like kits for writing drivers etc, which come with good documentation and are affordable?</p>

<p>Thanks!</p>

For embedded Linux hacking, simple Linksys WRT54G router that you can buy everywhere is a development platform on its own
http://en.wikipedia.org/wiki/Linksys_WRT54G_series
:
The WRT54G is notable for being the first consumer-level network device that had its firmware source code released to satisfy the obligations of the GNU GPL. This allows programmers to modify the firmware to change or add functionality to the device. Several third-party firmware projects provide the public with enhanced firmware for the WRT54G.
I've tried installing
OpenWrt
and
DD-WRT
firmware on it.  You can check those out as a starting point for hacking on a low-cost platform.