My employment contract states that I must give 90 day notice when leaving. Can they take any action against me if I want to leave after 60 days?

Theoretically your former employer can seek to enjoin you from working for anyone else until 90 days after you gave notice, but in the real world, unless you have very specialized skills (for example, if you were Britney Spears and were trying to leave your contract to perform in a venue early) there is virtually no chance that they would sue you, and virtually no chance that their suit would succeed if they tried.