• Data Books: (to look up integrated circuit specs) from National Semiconductor, Texas Instruments and Motorolla (also at onsemi.com)
• Electronics Vendor Catalogs: such as Radio Shack, Newark, Allied and Digi-Key
• Lab Supply Vendor Catalogs: such as Edmund Scientific
• Mechanical Supply Vendor Catalogs: such as MSC and McMaster-Carr
• Nuts & Volts Magazine: a great magazine for the electronics hobbyist/industry; good source of vendors for robots, microcontrollers, computer control, lasers, etc. (also at nutsvolts.com)

• See Chapter 17: Electronics and Circuits of the Introductory Engineering Design: A Projects-Based Approach textbook at http://itll.colorado.edu/index.php/courses_workshops/geen_1400/resources/textbook/.
• See North Carolina State ECE 480 home page at http://courses.ncsu.edu:8020/ece480/common/htdocs/ for electronics theory and demos/animations on electronics principles
• See How Stuff Works website at http://howstuffworks.com for topics including motors, appliances, light bulbs, etc.
• See Science Hobbyist website, an amateur science website, at http://amasci.com for how electrons flow in a circuit, how to test a coil, amateur science projects, etc.

CU Electronics Store

On-campus source for Electronic Parts, prototyping supplies, Hand tools, and cabling needs. Located in Electrical Engineering wing, room ECEE 1B10, (next to the ECE student lounge).

Sparkfun Electronics

Started by a CU Electrical Engineering Alum. Sparkfun is an online retail store that sells the electronic parts and modules to make your electronics projects possible. The website also has lots of tutorials and an enthusiastic user community. The website is a must see!!!
Sparkfun does not have a storefront. You must place a website order before you can pick up an order.
Boulder: 6175 Longbow Drive, Suite 200 (Located on 205 Bus route, Longbow at 63rd)
Website: http://www.sparkfun.com 

JB Saunders

A great Electronics prototyping store with friendly customer's service. For electronic parts and prototyping supplies.
Boulder: 3095 Sterling Circle unit 1 (55th & Valmont)
303-442-1212
Hours: Monday-Friday 9:30am - 5:30pm, Saturday 10am - 2pm
Website: http://www.jbsaundersco.com

Radio Shack

For electrical parts and pieces 
Boulder: 1895 28th Street (@ Canyon)
303-449-0635
Website: http://www.radioshack.com 

Acroname Inc.

Acroname's mission is to provide expertise, applications and high quality products in robotics.
Boulder: 4822 Sterling Drive
720-564-0373
Website: http://www.acroname.com 

McGuckin Hardware

The ultimate hardware store: Tools, hardware, plumbing, building materials, paint, sporting goods and lots of cool gadgets for your projects. If they don't have it, you didn't want it.
Boulder: 2525 Arapahoe Avenue, 303-444-1822
Located on Hop route, bottom of Folsom Hill @ Arapahoe
Website: http://www.mcguckin.com

Boulder Electric Motor Co.

For electric motors of all sizes 
Boulder: 3865 Walnut Street
303-443-1331

Hobby Town USA

Robotics and radio-control car kits and supplies
Longmont: 1935 Main St., Longmont, CO 80501, Phone: 303-774-1557
Website: http://www.hobbytown.com/Longmont
Westminster: 9120 Wadsworth Ave., Westminster CO 80021, Phone: 303-431-0482
Website: http://www.hobbytown.com/Westminster