Selenium Ide is a Firefox plugin that allows you to record and run the tests which you run using Firefox. You cannot perform advanced testing strategies in IDE like looping a single action for several times etc because you can’t use any programming language to write the test cases.
Selenium RC and WebDriver, allows you to choose a language of your interest to write the test cases. with the help of selenium RC or WebDriver, you can perform almost any kind of action, which you do manually. The major difference between RC and WebDriver is, RC uses a remote control to convert your tests into browser native code, your tests interact with the Remote control and the remote control interacts with the browser whereas WebDriver directly interacts with the browser without any Remote server, so the execution is faster.
Selenium RC is deprecated, and people are using WebDriver instead of RC