Ages ago, when I was going through a creative phase
I bought some special 'paper' that you could print off on your computer and then iron it onto a t-shirt, then peel off the back, hey presto! Obviously you need to invert the text prior to printing so that it is legible without the use of a mirror! However I still have those tops somewhere and they went through the wash quite a few times and came out super.
Now lets see if they still make the stuff.......