SprayR is a very simple little program that lets you convert png's gif's and jpeg's into source sprays. I'm not sure exactly how it converts so you're probably best off saving your spray as a png or tga with an alpha layer before converting, but apparently it can convert animated sprays too. If you're interested grab it here.

It's pretty simple to use, select your steam account and game from the drop-downs and it will put the files in the correct directory for that game. (It doesn't have an option for L4D or TF2 so you have to manually copy the spray across after convertion.)
Then select your image to convert, and hit convert. Boom insta-spay.

The FAQ on the SprayR site is only in German so I'm not sure what it's capable of, I just use it for converting to vtf.

aha this will be time saving, for a lazy bastard like myself .

Yay finally a spray thingy
Been after these for ages

Thankyou Mr Boylee

You can also read Chris|Gramps' excellent How To Make A Transparent Spray For Team Fortress 2

nice one the answer to my prayers - I use Gramp's tutorial - but always get stuck with the final step - getting the spray into game.
stickified

lol this still works?
Used that thing 5 years ago

Glad to be of service peeps, and Mac's right, Gramp's tut is definitely a must read if you don't know how to make sprays with transparency.

Oh and get out Hawk you're far too 1337 for this thread