Hi,
Yes - you can do this with IP SLA. In fact, this is exactly the kind of thing it's designed for.
As well as checking web pages (static ones only though) you can do tcp connects to any port, udp echos, dns requests, and loads more.
Check out the Q&A here:
http://www.cisco.com/en/US/products/sw/cscowork/ps1008/products_qanda_item0900aecd80652af2.shtml
Note that IPM (part of the ciscoworks bundle) is the Cisco GUI front end to IP SLA (there are others) and while not strictly necessary it makes life a whole lot easier. (The data is snmp-accessible so you could do you own thing here)
HTH - plz rate useful posts (not just mine!)
Andrew.