If you don't want to make your own redscale film, you can buy it from a couple of places online.
Feel free to add to this list.
Red Dragon 35mm x 36 Exposure ISO 100 Color Print RedScale Film
The Red Dragon RedScale film has landed and is prepared to scorch the earth, in crazy shades of red, yellow, and orange. Ultrafine Red Dragon Film is rated at ISO 100, and is a color negative (C-41 Process) film. Redscale is the name given to a technique of shooting photographic film where the film is exposed from the wrong side, in other words, the emulsion is exposed through the base of the film. People go to great lenghths to get their film backwords, but we here at Photo Warehouse have PRE_LOADED the RED Scale for you. The name "redscale" derives from a strong color shift to red due to the red-sensitive layer of the film being exposed first, rather than last (the red layer is normally the bottom layer in C-41 (color print) film). All layers are sensitive to blue light, so normally the blue layer is on top. - See more at: http://www.ultrafineonline.com/ulreddrrecop.html#sthash.v3cAZOII.dpuf
Old School Photo Lab
OSPL Redscale V1
Introducing our hand-rolled OSLP Redscale V1 film! 20 exposures on expired Kodak (05/2013). Great for those cool, unpredictable shots you just can’t get with standard film!
Nick & Trick
Nik & Trick Redscale
Bursting red photographs from this unusual film.
We advise a rating of 50asa but anything up to around 100asa produces results.
Varying exposure causes a change in colouration so it’s great fun to experiment with. More popular with our female snappers as per the sample image shown!