• Robot Marketplace is a reliable reseller of quality robot parts.  It's a great place to find everything you need.
• Need batteries?  Try Battlepack.com.  They make durable packs that can withstand the abuse robots dish out.
• There are several quality RC hobby sites on the web including Tower Hobbies and Hobby Lobby.

Organizations

• The Robot Fighting League is the main organizing body for robot combat.  They have a set of general rules that most competitions follow.  Most competitions have slight variations on the rules due to safety concerns in different arenas.  For example some events don't allow flame weapons.
• Western Allied Robotics covers Oregon, Washington, and British Columbia and uses a slightly modified set of rules.

Figure it out!

• Torque Amp Hour Calculator.  How many amps will your motors draw in your bot?  How much battery capacity will you need?  How fast will it accelerate?  Figure it out with this amazing tool!
• Kinetic Energy Calculator.  How much bang will you get out of your spinning weapon?  Find out using Team Cosmos's flexible tool.

Look it up!

• Search for an event close to you at the Builders Database
• How does your favorite bot stack up?  Look it up on BotRank!

Cool Stuff!

• I know it's off topic but if you are looking for a good portrait photographer in Seattle check out CAPhotogrpahy, and their blog.