We have had some people getting disconnected from our server and after making sure that it was not a 'server problem', we discovered that these clients that were getting disconnected had some additional internet service programs running while playing.
I spoke with them ( disconnecting clients ) in ventrilo and ALL of them had some additional internet programs running such as X-Fire, MSN, AIM and automatic update programs running.
These "AUPs" ( Automatic Update Programs ) such as anti-virus programs like 'Norton', 'Windows Update' and others automatically and periodically activate and search their respective websites for any available updates.
When the APU activates, it takes precedence or "first place" over any other internet connection such as online games and usually results in disconnecting you from the server.
After these clients shut down or disabled their APU and their other additional internet programs running, they no longer got disconnected from our server.
Put simply, just shut down any additional internet programs running while you are playing online and you will get a much better ping, less lag and no disconnections from server. 
It also helps to clear out your "Temparary Internet Files" folder, delete all cookies and clear the history ( history of websites visited recently ).
You want to get the maximum performance from your PC and internet connection while playing online games so it makes sense to have the least amount of programs running to help insure the speed responce of the game.
Pass this info on to your fellow online gamers so they too can have better online gaming.
