Sniffer tool to check latency

[Velvis]

Any one have an recommendations for a tool that can monitor latency? A client of mine is having "slowness" issues with a specifc web app.

 

[YeOldeStonecat]

Ixia has some great procucts, including free ones such as QCheck
http://www.ixiacom.com/products/display?skey=qcheck