Here are a bunch of sites that might be of use to you as you are building your robots. This list is not complete and there are many companies out there, these are just some that I know.
Blogs (and similar):
Autonomous Robots Blog – As the name says, a blog about autonomous robots.
eevblog – Electronics video blog with a forum. Good mix of newbie’s and experts.
hizook – Robotic news for academics & professionals.
robots.net – Robot podcasts with a blog.
Robots Pod Casts – interesting bi-weekly robot pod cast
Society of Robots – Beginner robotics tutorials with a forum
The Robot Report – Tracks the business side of robotics
Robotics Online – Industrial robotics stuff and robotics integrator certification
Adlink Technology – Lots of different computers
Advantech – Lots of different computer types
Beagle Board – Small, cheap, relatively powerful computers. Beagle board does not want you to use their computers in commercial mass-produced applications.
Diamond Systems – Small form factor computers and peripherals
Embedded Arm / Technologic Systems – Lots of low power computers and peripherals
Kontron – compact PCI and others
Logic Supply – Embedded computers with some rugged/fanless options.
Mini-Box – Lots of different SBC’s
National Instruments – cRIO & data acquisition
Raspberry Pi – The famous low-cost Raspberry Pi
Digikey – Large electronics supplier
igus – Good source for small (and large) lengths of various multi-conductor cable.
Mouser – Large electronics supplier
Newark / Element14 – Large electronics supplier
Sparkfun – Lots of random stuff including breakout boards
WireMasters – Lots of wire for a good price. Awful website if you don’t have exact item number.
Seeed Studio Fusion – PCB Manufacturing with a good cost, lead time and quality.
80/20 – Extruded metal and connectors – “Lego for engineers”
McMaster-Carr – A good source for just about anything. Plus fast shipping!
MFG – Online bidding for machining, molding, and other processes.
Timken – Bearings and chain
Motors: Controls, Feedback, Gearing, & Motors
Feedback (i.e. encoders)
US Digital – Lots of encoders
Digi – Small radios. Lots of 900MHz options.
Field Components – Networking and RF gear. Lots of cables and connectors.
L-com – Networking and RF gear. Lots of cables and connectors.
Bracke Mfg. – RF Gear. Lots of cables and connectors.
Streakwave – Wireless gear
Ubiquiti – Wireless routers (Click for more information)
Inertial / GPS / INS
Applanix – Complete INS solutions
Honeywell – High range IMU’s and other sensors
Microstrain – Lower cost IMU and inclinometers
Novatel – Complete INS solutions
X-Bow – IMU’s and gyro’s
Xsens – Low cost IMU and INS systems
Perception (Cameras, LIDAR, etc…)
Allied Vision – Manta – Some nice cameras.
Banner Engineering – I have never used their products but from the website it looks like they have a nice selection of radars and other sensors.
Continental (or Conti) – They have some radar, LIDAR, and camera solutions geared for automobiles.
Hokuyo – Smaller vendor that makes various smaller LIDAR sensors.
Point Grey – Used in a lot of machine vision applications. Nice cameras!
SICK / SICK USA– Large producer of rock solid LIDAR sensors. They also have other sensors.
Velodyne – Crazy awesome LIDAR sensors! One of their sensors has 64 lasers that returns 1.3 million points per second for full 360deg LIDAR coverage.
ROS – Robotic Operating System – framework for building robots
Coppelia Robotics – Robotic simulator. I have never used this but it looks interesting and Peter Corke (a respected person in robotics) mentioned it below.