The two main options are to buy a camera which has a spinner built inside, and you can change what colour you want the flash to be, or you can get ahold of a little 'pad' of gels, which you hold infront of the flash.
This got me thinking, I already have loads of filters sat around, why buy more? So I came up with the idea of mounting a filter ring over my flash. Read on to see how I did it.
Here is a little info on Lomography, and the camera I used -
The Holga is a camera made by Lomo, and is well known for being the cheapest and easiest way to get into Lomography.
To help define Lomography I have borrowed this paragraph from Batness' Instructable on 'How to paint a plastic camera.' (I think he may have borrowed it from wikipedia)
There are many people interested in using medium-format plastic cameras to take photos these days. Translation; film cameras are back in! Using this retro type of camera, you can take "vintage" ye-olde looking photographs.
This new trend was likely started by Lomography . Lomography emphasizes casual, snapshot photography. Characteristics include over-saturated colors, off-kilter exposure, blurring, "happy accidents," and photographers are encouraged to take a lighthearted approach to their photos, and use these techniques to document everyday life. (<--oh noes Wikipedia!)