First,
See this thread
Then read this.
For big, corporate soponsors, it's going to take a lot of work. We currently don't have any either. You can write letters to either the local or corporate offices of soem companies near you. You will need to write dozens of letters because most of them will just be ignored. You also need to have a followup phone call 2-3.5 weeks after you send the letter. I can send you a copy of the letter we currently use if you like.
You can also try to fundraise/obtain sponsors on the local level. Have a few people of your team just go in to your local home center and ask to to speak with the manager. If he is busy, arrange another time. When you speak with the manager, have a nice presentation ready with something like a binder to show who your team is, what you do, what you need, and why this place should help. They will probably be able to give you a percentage off all purchases or a gift certificate or possibly a donation.
You can also divide up the back of your team shirts into about 24 business card size rectangles. Sell these as advertising space to all the local businesses for $100-$200 per square. You will need to be able to tell them how many people will be wearing them, how often, and when the shirts will be made.
Another thing you can do is go around to perhaps the same businesses for the back-of-shirt advertising and offer them a plaque (spelling? - sounds like "plack") that has a photo of your team (students, mentors, engineers, robot(s) all included) and a place where it says "A proud supporter of the 2003 Timberlane Tantrum Robotics Team". You can probably get these made for around $30 and sell them for about $150. They can hang it in a public place of their store/restaurant to show people that they have community involvement.
You can also have fundraiser nights at a favorite restaurant nearby. Many restaurants are happy to set up an event for you where you take something like 20% of the sales that night because it's all tax deductable for them. Just be sure to stay away from Baja Fresh (if there's any of those near you) because you'll hardly make a dime.
Car washes can also bring in the bucks. If you can do it in a high traffic area in a place near your school, you are bound to make minimum $200.
Last, if your school has lunch carts or a cafeteria, try to see if members of your team can work in any of those during lunchtime. We get $25 per day for 2 students on one cart for 20 mins. Not bad.
Remember for any outside funding or fundraising, you will most likely need to have your team's or school's tax ID number on hand.
Hope this helps. If I can be of further assistance, let me know.
- sanddrag