[Rick#2]

Don't bother asking Telus anything; they will just tell you to use the international roaming SIM and pay up the butt for their outrageous international roaming rates.

I was in Manzanillo in September and just bought a Telcel Amigo SIM card from an Oxxo store for about $10. I know Cancun is on the other coast but Telcel pretty much has the monopoly there so you shoudn't have a problem. It'll really help if you know Spanish because to activate the SIM you need to call in to get the instructions, but if you find a Telcel outlet (they're everywhere) you can probably get someone that speaks English to help you.

Just make sure you unlock your phone's SIM capabilities, be it through cmonex and Olipro or off of eBay. Shouldn't cost you any more than $15 or so. You won't be able to use the Telcel SIM card if you don't SIM unlock (not the same as HSPL) your phone first.

Good luck amigo! Rather than paying $5/minute with Telus it's about $1/minute through Telcel, plus you can get pay-as-you-go data down there for pretty good rates.