>Official Site: Contains deck building rules and the current ban list. mtgcommander.net
>Deck List Site: You can search for decks that other people have made. Authors often have comments that explain their decks strategy and card choices. tappedout.net
>Statistically see what everyone else puts in their commander decks based on what is posted to the the internet. edhrec.com/
>Find out what lands you can add to your deck, sorted by category, based on a chosen Commanders color identity. manabasecrafter.com/