Application Monitoring Tools

Hey guys i work with a outsourcing company. We have many process running over here any many different applications are being used in different process, mostly om VMWare and Citrix Platform. Is there any monitoring tool available for monitoring these application's performance.
Any help will be appriciated.

Try Nagios or Zenoss.

thanks gagamboy for the reply.
But these tools are network monitoring tools or application monitoring?
as we already have 3-4 network monitoring tools available with us.

What kind of applications are you looking to monitor?

@KiLLaBeE - say like VMware and citrix based applications.
@gagamboy - the tools you have mentioned are combined thing of network & some application monitoring... right??

Yes, as far as I know.

I think Zenoss can monitor applications too, like citrix or even vmware. Check out their site www.zenoss.com/


Cheers!