By default all versions of Windows do provide a task manager where you can see the programs running, cpu usage and memory. But with Windows Vista there comes another out of the box feature called as Resource Monitor. This program categorizes all the running programs according to their usage in the filed of Network, Disk, Memory and CPU.

So now if you want to find out how  much Yahoo Messenger is using in terms of Memory and Network this is the right place to check it out. More over this place is the right place to find which programs are accessing your network or internet so that in case something fishy is running you will get to know. So instead of using any third party tool you can use this safely and with complete trust.

To Access this program just invoke the task manager and invoke resource manager under the performance tab. However you will need administrative rights for this.