I am interested in using samples of news media soundbites in my music,
particularly public statements by political officials.  For example, I
heard an electronic dance mix with the voice of George Bush mixed in
saying certain things, the song was sort of a political statement,
etc.  My question is as follows:
1)  Legality and Copyright issues:  Does the Fair Use clause of the
Copyright laws cover political commentary and criticism in this way? 
Does the song writer/composer need to get permission to use sound
bites of public utterances by polticians, news commentators, reporter,
and celebritiess aired on TV or the radio?  Does Fair Use for
political commentary/criticism only apply to paid public officials
such as the president, vice president, governor etc?  In short, whose
voices can I use in my songs under Fair Use and whose voices do I need
permission to use?  Do I need permisson from the media source who
aired them (ABC, CNN, Fox, etc)?  Bear in mind that the use of the
sound bites are for purposes of political commentary and criticism.
2) Assuming I have found a means to legally use news media soundbites,
now comes the question of whether I must record the sound bites as
they come over my radio/TV on my own, or whether I can get them from
the media sources themselves (I don't have to be waiting and recording
sound bites in 'real time' and sound quality is better this way,
obviously).  Do media corporations like ABC, CNN and Fox have audio
archives I can access to find the sound bites I am looking for?  Do
they allow people to access and use recordings from their broadcasts? 
If they offer such services do they charge fees?  Terms and conditions
may vary from one corporation to the other on this question, so just a
few examples from the largest and most popular media corporations will
do (ABC, CBS, CNN Fox etc).

1) Legally, according to the fair use act, if its just for political
commentary/criticism then technically its fair use.
(http://www4.law.cornell.edu/uscode/17/107.html) Of course if you were
sued and brought before a judge the four factors (listed in the above
link) come into account and its upto the judge at that point.

2)Youcan download ABC's (just using ABC, im sure its the same for all
of them) sound bytes for "you may download one copy of the materials
on any single computer for your personal, noncommercial home use only"

Also in the terms of services is a clause about the AP: "Associated
Press. ("AP") text, photo, graphic, audio, and/or video material shall
not be published, broadcast, rewritten for broadcast or publication,
or redistributed directly or indirectly in any medium. Neither these
AP materials nor any portion thereof may be stored in a computer
except for personal and noncommercial use"
(http://disney.go.com/corporate/legal/terms.html for both of those quotes)

So again for your own personal home use youre okay. From the Fair Use
clause you could get away for taking portions for critism. Making into
a song may be more difficult to prove that its non commercial.

As for actually getting the sound bytes you would need to contact ABC
(or any other station) and purchase them. As far as i can tell there
no sound bank availible for public use. Along the same lines I saw an
interview with michael moore in which he commented on how expensive it
was to purchase all the various sound bytes from reuters and the AP.

So in summary you can use the sound bytes, but only for your own use.
You might be able to put into a song, but if the organization that
actually took the soundbyte was able to track down its use (unlikely
considering that there are so many reporters at any event) and bring
you to court a judge may not think youre covered by the Fair Use
clause. If you do decide to purchase the soundbyte you would need to
actually contact the organization and they may expose a database of
sound bytes that are not available to the public.

Hope this helped.

Maybe it would just be simpler to write your own copy and have someone
who sounds professional read it into a mic at  a recording studio. 
Then it's really yours.