Mark,
I realise me and Ewan arent giving you all the answers, but thats kind of the point. If we tell you what to do, it would be our idea of whats a good robot, not yours.
With respect to sponsorship, Ewan definetely has more experience than me, but my advice would be to ask anyone you can think of. Anyone and everyone you think is remotely connected or interested in your robot. If you dont ask you dont get.

I dont know how Ewan did it, but hes managed to sort out lots of different sponsorship deals. Most are connected with materials and components from what I can tell.
I recently got a large amount of money from BT and a controller worth even more from National Instruments, both for my university project. If you explain to companies what you are doing, why its worthwhile and what they can get out of it, they are more likely to give you stuff. Ive never manage to sort out sponsorship for my combat robots, although I have been given some machining time.
Chances are, any company me or Ewan can think of to ask for sponsorship weve already asked, so theres little point you asking them.

I think a website helps, but not has much as having a clear plan of what youre doing, when and how.
For stuff like this theres a massive resource of information on the internet. How many build reports have you read? There are probably loads of people in a similar situation to you and you could see how they did it. Most of your newbie questions can be answered with a quick google (like do I need 4 crystals for a 4 channel radio?)
By all means come back and ask if you get stuck though.
Have you read Team Nightmares tips and FAQ? (http://www.robotcombat.com/tips.htmlhttp://www.robotcombat.com/tips.html) its a really good source of information for newcomers. Have you gone through Team Nightmares links page? It used to rate the links based on how much information they give, overall quality etc: http://web.archive.org/web/20031210110330/www.robotcombat.com/links-us.htmlhttp://web.archive.org/web/200312101.../links-us.html
Ive visited most of those sites and they give you really good picture of what works and what doesnt.

I wonder how many roboteers get their information from other webpages?
Ewan: how many sites do you think youve looked at?
Also Ewan, what did the companies get out of your sponsorship deals?

I think that covers everything I know about sponsorship!
Mark