No , but getting a female to female should be easy enough, then putting that on either a male to Y adapted 2 female should be easy enough.
we play this game at RadioShack Called "Make that adaption" :-) Whoever can make the adaption in the least ammount of connections wins. Eventually i just cut a wire, and put my own end connection on.
But let me show you what I am referring to.
http://www.radioshack.com/product/index.jsp?productId=2103870 <-- stereo Y wire, A wire because it does not stick out very far like...
http://www.radioshack.com/product/index.jsp?productId=2102527 <-- stereo Y Adapter.
http://www.radioshack.com/product/index.jsp?productId=2102697 <-- female female adapter
Just examples. and crashing 2 analog signals to the same speakers, is possible, if they are both line level, but you can have many possible problems with that, so you will have to test for yourself.
A ground loop isolation http://www.radioshack.com/product/index.jsp?productId=2062214 <-- 1:1 transformer with rca jacks , can come in handly when getting signals between devices, would also have to be adapted to Again , but we can make that adaption in 3 :-)
They do have atenuated connections and atenuation adapters pre-built, which might become more nessisary with Headphone outs on laptops, which can have high output levels. http://www.radioshack.com/product/index.jsp?productId=2103841 <-- some kind of MONO resistered 1/8 wire (not good).
But like Gurken Papst pointed out, it is just a 10c resister tossed in there. It is often better to put your own in, so you can change it up or down appropriate for the levels.
Radioshack was just the source for pictures, you should be able to get that stuff online anywhere.