I've found the advice (and recipes) on PostPunk Kitchen to be useful (and tasty). She has a section on egg replacers, how to use them and what they are best used for.

You can find it at: http://www.theppk.com/veganbaking.html

Also if you do a google search for egg replacer cookie baking you'll come up with many other suggestions and opinions.

I hope this is helpful.

Ellen