If you're an independent contractor, how do you charge clients?
turtle3: $X to make website match a given layout/image in FF and IE, where X is based on your approximation of difficulty after reviewing the provided material.  $Y/hour for each modification after the initial layout is complete, where $Y is 2 or 3 times what seems a reasonable rate to you.This will do a few things:
1) Cause the customer to get their act together up front, because they would rather only pay $X.
2) Minimize your annoyance at the back and forth, because you are making what you feel like is a lot.Mostly you want to avoid getting into the $Y/hour area, because it just sucks, mostly.  Don't be afraid to set $Y to $50 or $75.  You -want- it to be a deterent as much as a way of making money.  Also, if you don't set that rate high, they won't value your work.  If you are willing to do it for $10/hour, you are barely a step above a fast food worker, and will be treated as such.  By setting a high rate, you say: 
1) You know you have skills that not everyone does.
2) You value your time, which implies you will value theirs.
3) They better take requests seriously, or they will pay for it.If you really want to work for $10 an hour, go ahead, but you are undervaluing your work, and it won't be maintainable.(Note: My comment takes into account the current $10-$30 range the poster mentions in a comment below.)