Statistical packages
Statistical software is one of the most important software for epdiemiologists. For a detailed review see the list of comparison of statistical packages from Wikipedia. The most important ones are listed here
R = Open source statistics package
Stata = statistic software
SPSS =statistic software
GraphPad Prism = statistic software focused on graphs
Openepi = Open Source Epidemiologic Statistics for Public Health
Atlasti = Qualitative statistics software
Joinpoint = analysis of trends using joinpoint models
Atrisk = risk analysis using Monte Carlo simulation
Quick guide for experienced users of other statistical packages (e.g., SAS, SPSS, Stata) who would like to transition to R. http://www.statmethods.net/index.html
GIS software
Geographical information systems are used for displaying and analysing geographic data. For a detailed list see the list of GIS-software from Wikipedia. The most important ones are listed here
Acrgis = frequently used program
Quantum GIS = Open source GIS program
Regiograph = business mapping software
Data entry software
Epidata = data collection instrument released by the non-profit organisation "The EpiData Association"
Epiinfo = data collection instrument by CDC
Social network analysis
Cytoscape = Open source social network analysis tool
Online questionnaires software
Limesurvey = Open source online questionnaire tool
Select survey
Survey monkey
Voozanoo