Vista Home Premium, SP2, WLM 14.0.0726

Not sure which newsgroup to post this :
I intend to install a webcam on my laptop in order to keep in touch with my sister far away.
What do I need to know ? Do I have to activate another program i.e. messenger ?
When I installed my WLM, I did not install Messenger and other related programs.
I need to know enough to tell my sister who knows even less.
Thank you.