This paper attempts to give a survey of some free software tools for wireless sensor networks. It targets teachers and students who might have the need for education in this area. As a first stage in creating this survey, a process of software collection is presented. First collection step is search through the Shanghai list for the first 50 universities. From these universities, available information about used software for wsn-related courses is collected. Additionally, other wsn software surveys are considered. Then, only free, open source and available software are kept, because they are the easiest for students to get it. Then evaluation based on topics coverage and software features is done. Topics are selected from IEEE Curriculum guidelines, while features give emphasis on practical usage from user aspect. Selected topics are embedded systems, computer networks, operating system and system resource management. Features used in the evaluation are support for GUI and command line, programming language learning overhead, ease of installation, extensibility, and platform portability. As a result, following software tools are described: TinyOS, Prowler, Riot, Castalia, Avrora, Shawn, TRMSim-WSN, and Shox.