http://dictionary.reference.com/browse/impeached
Usage Note: When an irate citizen demands that a disfavored public official be impeached, the citizen clearly intends for the official to be removed from office. This popular use of impeach as a synonym of "throw out" (even if by due process) does not accord with the legal meaning of the word. As recent history has shown, when a public official is impeached, that is, formally accused of wrongdoing, this is only the start of what can be a lengthy process that may or may not lead to the official's removal from office. In strict usage, an official is impeached (accused), tried, and then convicted or acquitted. The vaguer use of impeach reflects disgruntled citizens' indifference to whether the official is forced from office by legal means or chooses to resign to avoid further disgrace.