Question : Who is current ISP?

Is there a way for me to (programmatically) determine who is the ISP giving access to the Internet?

Thanks.

Answer : Who is current ISP?

Try a traceroute to any website and you should the ISP servers show up immediatly after the packet escapes your network.  You can do this by going to a command prompt and typing the following information:

tracert www.yahoo.com

The resulting information will be the steps it takes to get to the yahoo home page.  Meaning these are all of the routers that your request goes through in its attempt to contact yahoo.com.  You will notice in the first couple of steps some IP addresses that look familiar if you have a LAN and then once it leaves your network it goes to your ISP's servers and routers first.  From there it could go anywhere in the world trying to get to yahoo.

Good Luck and I hope this helps!