Istakhara

Salaams

Can someone please shed some light on this topic.

What exactly is Istakhara?
Is it allowed or forbidden?
Who can perform Istakhaara?
Under what circumstances can one perform it?
and above all How to perform Istakhara?

I have usually heard about people who do it or get it done to be sure about a marriage proposal, and some are really strict about it meanning they do not go against the Istakhara verdict. So can someone explain all of the above.

thanx

Here’s one link that may help, http://www.jamiat.org.za/istikhaara.html

And here are some threads you might be interested in,
http://www3.pak.org/gupshup/Forum13/HTML/002325.html
http://www3.pak.org/gupshup/Forum13/HTML/001184.html