I have no parts of dealing with the business end other than being hired on to do their web site. If the escort business gets stung in a VICE operation, could I be charged as the webmaster?
You probably have little to worry about in terms of conviction, but your knowledge of the system may have a bearing - particularly if it was used to run some sort of vice ring - and the police may be interested in chatting to you. A quick inital consultation with an attorney may be advisable if there's a chance the police may be knocking at your door at some point. Even if their initial intentions are friendly, you will need legal help and advice.