Best SIM card for Cellular Net Access?

[grandmaster]

Hi,

I'm spending three weeks in the USA in October. I'm taking my laptop which has a cellular modem capable of HSDPA speeds.

Can any one recommend a 'pay as you go' SIM card I can buy from a store that includes a decent data allowance so I can access the internet from wherever I am in the US? Also some idea on where I can buy the SIM from would be useful too.

In the UK I can get unlimited HSDPA for £1 per day. Something similar for the US would be great.

 

[Dew]

Cingular Pick Your Plan 200 mins @ $30 + Unlimited Media Net @ $20. So, about $60 total for a month of service.

 

[grandmaster]

Great, and I can get that in any store? Maybe even at SFO airport when I arrive?

 

[grandmaster]

Hmmm, so I get to San Francisco and the Unlimited Media Net deal is dead. $9.99 for 5MB!! WTF!

Can any one recommend any alternatives?