Open source applications are computer softwares, that are free to download along with the source code. These softwares can be used, modified, improved and redistributed. These softwares are normally developed by a group of people in an collaborative manner and often found hosted in the public domain. The open source applications are freely distributed along with the code. When the code is not available in a particular site, it is the duty of the software developers to publicize the exact destination from where the users can obtain the code. The open source software developers always treat the users as their co workers, they encourage them to submit additions to the software, code fixes for the software, bug reports, documentation etc. While on taking an open source project the developers release the first version of the software as soon as possible, in turn they expect the users to modify and add certain new features. The open source applications are always available in two versions, one version is a stable one with few features, the other version is the development version, which is applicable for the immediate use of new feature by the users. The users who go in for the development version are always at a risk of testing the new code on the other hand they get a chance to fix up the bugs, errors and innovate a new code. When the users develop additions or modify the code, the entire project is revised with the help of tools such as Concurrent Subversion system or later sub versions , and the source files are centrally managed, and the additions are implemented to the source file. Open source applications do have a license. The license always grants permission for the users to copy, modify and re- distribute the source code. Some of the examples of open source licenses are Mozilla Public License, MIT License etc. The highlight of the open source application is that, it allows the user to use and modify it according to his own needs and requirements, without the permission of the software developer. Small enterprises always find open source applications as a boon. Linux is a famous open source application which is used worldwide. It opens room for the users to modify and use it according to their requirements. It is also cost effective, it helps the organization to save money, which is to be wasted on legal softwares. Some of the famous organizations involved in developing open sources softwares are Apache Software Foundations, the creator of Apache web server, Eclipse Foundation, A team of members under Linux Torvalds, innovators of Linux operating system, Mozilla Foundation, Object Web etc. Open source softwares are developed and they are available for all fields and all catergories. Some good examples are Newgen Lib, used for Library Integrated System, Bio Eclipse and Bio rails , open source applications for Bio informatics, Twinkle used for Voip Soft phone. Open source softwares have many advantages, like being cost effective, greater penetration in the market, updating with the new technology, reliable ( because it is tested by many developers). One of the negative aspect of this is that it allows the hackers to elucidate the loopholes of the software.