Proposals are expected before June 23 for one tyre supplier. As Michelin is probably retiring at the end of this year, we could see a Bridgestone only grid as soon as 2007. Another advantage for Ferrari... hi, hi, hi, hi....
The rules are here
Some people have complained that it doesn't give much rights to the tyre supplier: you cannot use the F1 logo, you cannot get "free" support from pilots, you only get your uniforms, trucks, tyres and driver`s "podium caps" with your logo...
But I would say they freeze the specification, so the cost of delivering the "frozen" tyres should not be high.