Hi there Hany,
I'm not sure there are any rules as such.
I'd suggest that you could write to them as if they are friends, ie: using a fairly informal tone. Of course, being a new penpal you might want to be a little cautious about giving out any personal information.
Here's a page I found that gives some basic advice...
http://www.womenatwork.co.za/penpals.htm
I hope it helps.
:D




