Do anyone of you Fools invest in preferred stocks?

I do not.

What are the pros and cons?

A preferred stock is sort of like a cross between a bond and a common stock. So the pros and cons would be somewhere between the two.

How does one find which companies have issue preferred stock?

There is a preferred stock message board, but, it does not seem to be active. http://boards.fool.com/preferred-stocks-116464.aspx
The might discuss preferred stocks on the Fixed Income message board http://boards.fool.com/bonds-fixed-income-investments-100135...

Bob