Making Slides with LaTeX

While doing slides for one class I am in I had to get myself familiar with the seminar documentclass that was developed by Timothy P. Van Zandt. The User Guide is a good document to refer to while learning to use this package. My first problem while using this was that when I created my .ps file all the slides were uppside down (seascape instead of landscape), but that was easely solved by putting the line

\special{! TeXDict begin /landplus90{true}store end }

in the preamble of the tex file. This seems to have something to do with how dvips works while converting from .dvi to .ps but according to Tom Rokicki (the developer of dvips) the above line fixes that and it did in my case.

Making Posters with LaTeX

To make a poster with latex use the a0poster class file, you can get the relevant files (class and style files) from here. Since debian doesnt distribute it but in source files, I had to manually add them by putting those two files into /usr/local/share/texmf/tex/latex/a0poster/ and then execute texhash and I could start making posters with latex.
Here is a useful page with good links at the bottom about making posters in latex.