I use Latex for writing articles. You can download all the relevant packages from CTAN. I prefer using Kile as an editor for writing Tex files.
A useful package that comes with Latex is Prosper which is used for making presentations. I used an enhancement to Prosper known as PowerDot and found it very useful. Though you may have to spend some time learning this software for your first presentation, you will not waste any time on subsequent presentations and can just concentrate on the content rather than the slides which are automatically taken care of by PowerDot. You can learn somethings about PowerDot from Hendri Adriaens's website. You will need to download packages like prosper, xkeyval, xcolor, pstricks, enumitem also before using powerdot. You can download all these and many more packages from CTAN. You need to keep these folders in the appropriate directories in your file system and "texhash" them.