I have noticed that more and more hotels throught the USA are beginning to offer internet access in the form of broadband access. This would be much like the cablemodem or DSL service which is growing like wildfire. Charges for this service vary. I have paid as little as $3 per day, to as much as $12 per day. The $12 a day service offered no support from the hotel. The $3 service in a Texas Marriot included cables, software, a detailed instruction card, and a toll free number for tech support.
To utilize this feature, you use your own laptop computer, and it must have a NIC on it. (NIC is Network Interface Card, aka Ethernet card, aka LAN card. It's input looks like a big telephone jack) Many newer laptops have this built in or you can buy one to plug into your PCMCIA slot for about $40. I have a combo 56K modem/LAN card that sells for about $140.
While this is a growing trend, those that do not offer this service would most likely either have a data port on the phone or wall where you can make an outbound "call" through your own modem to your own dial up service. This call usually equals the amount of a local call, which ranges from free to about $2.
The really backwards antique hotels usually have a way that you can unplug your hotel phone, and plug your modem into it's place. Then, you can call a dial up if you configure your modem properly to get an outside line.
I haven't experienced a hotel that has internet access other than those 3 options. As long as the dial ups though a modem are a local call or toll free call, there should not be any time limit. If your dial up is a long distance call, the normal EXTREMELY HIGH long distance rates will apply. If the connection is a high speed connection through a LAN, it is a 24/7 connection with unlimited usage and a daily rate.
I have seen hotel rooms in Vegas that offer in room FAX service, and I have heard of in room e-mail (not in Vegas) that was e-mail only...not internet.
I suggest calling AND e-mailing the hotel in advance...maybe more than once. Get at least 3 different people to decribe the service and it's fees.