gns3.net - "roll your own" network in a virtual environment, using real Cisco and & Juniper router images
evilrouters.net - network & router blog
mcmcse.com - free info on various IT certification exams, practice tests, etc.
ioshints - Cisco IOS hint
networkengineerblog- lots of simple, to the point posts with useful cisco commands.
jaluri.com - a Cisco and Networking blog aggregator
etherealmind.com - a networking blog
