Cor,
Please go back to school before you start offending other posters like Bob. I have no idea how you got your MVP or in what area your MVP is in, but I can tell it's not in .NET. "A webservice = aspnet" is an absurd statement. .NET Web services can be accessed from anywhere with anything and on any platform as long as that anything runs .NET. You can even call a web service from managed SQL since SQL 2005 came out, and you could call Web services from Windows Application since the beginning of .NET.
Bob, your question was 100% valid. To set timeout on a web service, first instantiate that web service. Let's say you called your web service MyFunkyService when you added Web Reference to it to your project. Then you'd instantiate it like this:
Dim myServiceInstance as New MyFunkyService.MyFunkyService
"MyFunkyService" repeats twice because by default when you add a web service, a proxy class is created and placed in the same namespace as class itself, so the first "MyFunkyService" refers to the namespace while the second one - to class name.
To set timeout to, say, 360 seconds, write:
myServiceInstance.Timeout = 360000 'in milliseconds
I think you're right that default is at 100 seconds or 100000 milliseconds.