in case you want more information.
There are lots of interesting papers on quantum cosmology and string cosmology in the archive.
http://arXiv.org/
Michael Turners recent paper "A sober assessment of cosmology at the new millennnium".
http://arXiv.org/pdf/astro-ph/0102057?
The short description of Guth's inflation but has some details.
Guth wrote a great popular book on his inflation 'The Inflationary Universe' which covers the history of modern cosmolgy as part of the intro for his discussion on inflation.
http://nedwww.ipac.caltech.edu/level5/Guth/Guth_contents.html
A bit about inflation from Andrei Linde.
http://www.sciam.com/specialissues/0398cosmos/0398linde.html
Stephen Hawking has written extensively on his 'no boundary cosmology'.
I always felt that the inflation idea is really ingenious.
Maybe you'll want to know a bit about the pressure term in the metric.
http://super.colorado.edu/~michaele/lambda.html