I bought this shield Adafruit Motor/Stepper/Servo Shield for Arduino kit [v1.2] : ID 81 : $19.50 : Adafruit Industries, Unique & fun DIY electronics and kits and on this page on how to use it http://www.ladyada.net/make/mshield/use.html
A few paragraphs down it says "Need more power ??" and explains that if you piggyback the IC you can get double the current. So that's what I did. However the IC now generates a lot of heat, its over 35C. And I have to take it out.
Why is this happening and is there anyway to reduce this heat without an IC heat shield as I do not have one to hand ??
More power through the IC means more heat. However, ICs are usually rated to take a fair amount of temperature before failing. 35 C (less than body temperature) is not a problem.
Typically, ICs are rated up to 85 C, and some are rated higher (such as 125 C) -- check the data sheet to make sure.
If you get too hot, the next step is to add a heat sink with some heat sink grease or glue. There are specific "chip back" heat sinks you can get, but any strip of metal bigger than the chip will work somewhat (more is better.)