VPN solutions

Hi All,
We're doing hotel business. The hotels crossed nation want to connect
the central reservation database in corporate office to get the
reservations, and hotels send their availabilities updates to the
database. We're going to use VPN to do this kind of 2-way
communications. 
If set a Cisco router in corporate office and let each hotel to use
client software to make such connection. How many VPN connections can
have simultaneously? Is this a good way to go? Which Cisco router is
better?

Thanks in advance.

Roger