Help with designing/making own family reunion t-shirts

I'm coordinating a family reunion for August. It's a come-as-you-are
and bring-yer-own-eats. Nobody wants to spend money!!!

What I want to do is write up directions for how folks can create
their own t-shirts using our logo, a plain white t-shirt, a color
computer printer, and whatever is needed from a craft store to do an
iron-on transfer .

I have actually designed a "double logo" that I want to combine into
one graphic for folks to use and I don't know quite how to do that
either.

http://members.aol.com/americanaatti..._2004_logo.gif

http://members.aol.com/americanaatti...mily_chain.gif

What I want to do is combine the two logos with the name logo larger
than the family chain pic and follow that with a line of text that has
the date and location.

Can anybody help lead me in the right direction of how to
accomplish???

I want to send a global email to participants that there is a link
with detailed directions of how to "make your own reunion
t-shirt!!!"....

.....but I am totally clueless where I sit!!!

Any help pointing me in the right direction(s) as to software needed,
supplies (and what they are called) would be greatly appreciated.

Thanks.

Kathy