VB.NET somehow listen for event?

Ok, so..

I have a script on my server that backs up files every 12 hours and stores them in a protected web directory. I have no problem making connection to the directory, checking for new backups, and downloading them.. At the same time the backup occurs, I have a php script run and update the backup version file and the vb app downloads the latest backup according to that.

What I would like to be able to do is somehow have my application listen for a command or even a single packet sent from my PHP script or server itself to initiate downloading the backups. Is this possible? What will I need to do?

you can listen to a port for a message ref (http://stackoverflow.com/questions/3301134/how-to-receive-udp-packets-from-any-ip-and-any-port)... That is C# but .net supports C# and vb so I assume you can find something easily for vb... the key words i used were C# listen packet port (i don't say that to be a jacka**; I know from personal experience that sometimes know what to look for can make a difference)

let me know if that's what you need; i know it can be done i used to send PLC packets over devicenet to a converter that sent a packet on a multicast network and was picked off by a .net app