Salary Insights on LinkedIn

This is a feature on LinkedIn which anyone can use. If you are a premium member, you can just use it but if you are a free member of LinkedIn you will need to enter your salary information. It's anonymous, and although it might seem annoying it's actually really useful if you do enter this as it is how LinkedIn gets their benchmarking data.
As well as finding out what a possible salary range is, it also shows you current vacancies and salary by location as well as a few other things.