I haven't been able to find any news stories on this yet, but it appears that house republicans are now attempting to impeach Obama under article II, section 4 of the Constitution, for using force in Libya without a declaration of war from Congress. The resolution, "expressing the sense of Congress that the use of offensive military force by a President without prior and clear authorization of an Act of Congress constitutes an impeachable high crime and misdemeanor", was submitted by Mr. Jones (I believe this is Walter Jones, R-NC) on Wednesday.
Text at the Library of Congress website
PDF of the Resolution