I need to have a program running in a Unix server, that every time the data
in a table in a DB is modified, triggers to call an application found in the
operating system that sends update info at the same time to several client
apps written in VB.NET.

Anyone has an idea of how to raise an event at the VB.NET client app every
time new info comes in?

Another possible solution would be having a timer in the client that checks
some communicating channel for new info and every time it finds info, then
it updates the user screen at the client.  Should I use Sockets, UDP or
what?

Any ideas on either option, or maybe a different way of solving this
problem?
Thanks a lot for your help,
Carlos.