I've been in contact with these people http://www.shunra.com/free_ve_desktop_standard_trial and have downloaded their 30 day trial software. I'll let you know if its any good. I noticed that Microsoft's XNA framework has built in support for testing network conditions. I might have a go at producing a utility that does something similar for us Delphi users

Thanks for all your suggestions for delaying the packets. I also need a solution that will drop packets and mix up the order they arrive so I also need a more advanced solution than just a delay. Hopefully this trial application will provide what I'm after.