Cool, the Mikrotiks are perfect for getting into routing as the RouterOS docs are very in-depth w/ lots of examples (yay, wikis): http://wiki.mikrotik.com/wiki/Manual:TOC

You can install OpenWRT to compare although it looks like installation is a slight pain: http://wiki.openwrt.org/toh/mikrotik/rb450g - it's probably easier to install as a metarouter if you're just playing w/ it: http://wiki.mikrotik.com/wiki/Manual:Metarouter