Specifically, I was amused today to see the Daily Show putting out a rather good piece on Dick Cheney's argument that his office is not part of the executive branch of the goverment of the US. The video is called "non-executive decision" on their recent videos, and is much the most amusing way to further your knowledge of the issue, for as long as it remains up on their website.
If you should wish to do things the old fashioned way and "read" about it, then you could point yourselves in the following directions. The headlines also, in and of themselves, paint a lovely concise story of their own.
LA Times: White House Defends Cheney's Refusal of Oversight
Boston Globe: Cheney asserts he's part of the legislative branch
Raw Story: Democrats plan to cut Cheney out of executive funding bill