I try to ensure that my kids do not consume many artifical ingredients and colours. But the end result still needs to be beautiful- especially for parties! Luckily, I had some natural food colouring and sprinkles and some ideas on how to make some lovely pink drinks.
In Canada and the U.S., a good company for natural colourings and sprinkles is India Tree. You need to watch the labels though as only their "Nature's Colours" line is made of natural vegetable colourants. Usually price is a good indication of the more natural ones as they cost substantially more.
www.indiatree.com/products/decorative/natures_colors/index.html
I usually get my sister to smuggle some natural colourings in from the U.K. as they are quite a bit cheaper there as the U.K. government has asked that most food colourings be removed from food items for several years now. So instead of Red Dye #40, the label reads "beetroot" and instead of Green Dye, the label reads "spinach" or "spirulina". The only sure way to avoid artificial colours in North America is to buy organic, as those items that are certified organic can only contain natural colours.
If you don't have access to natural food colourings, beets, raspberries or strawberries are excellent ways to get some vibrant colour into your drinks and frostings using what is in your fridge or freezer. 
I wrote about using some beet colouring way back in February if you want to check it out: http://www.mintgreenapron.com/2011/02/pink-icing-pink-lemonade-pinkalicious.html And although I haven't made it yet, I have also read an article from the U.K. about whizzing up a little spinach, a touch of lemon juice and sugar in a blender to get a lovely pale green colour. Or you can check out this post that I found online that looked interesting from the Old School Pastry blog: http://oldschoolpastry.blogspot.com/2011/01/how-to-make-green-food-coloring.html
There are studies that show the adverse effects of artificial colours on children (including allergies, ADHD and cancer) and so I try not to take any unnecessary risks with my children's health.
Really, we don't need bright red cookies at Valentine's or orange and black ones at Halloween. Add colour with natural, fresh foods or flowers from the garden. We had vibrant fruit skewers made of strawberries, grapes, canteloupe and watermelon to add some colour to the table at our party.
I hope that this post inspires you to try something new and beautiful in the kitchen...something more natural and less toxic for you and your family!
