Here are some free tools (mostly open source) that I use to help in my job as a software developer.

Winmerge – an Open Source differencing and merging tool for Windows. WinMerge can compare both folders and files.

PSPad — this is a nice code editor.  Notepad++ is great as well.

FileZilla — a great, free, open source FTP program. Supports SFTP as well.

GIMP — It’s not photoshop, but if you are working on graphics for use in an application, it’s more than adequate.

Microsoft FXCop — this application analyzes managed code assemblies (.NET Framework common language runtime) and reports information about the assemblies, such as possible design, localization, performance, and security improvements. You can configure which rules to have it report on. I turn many of them off. The latest version has a glitch that keeps telling me there is an update available even though I’m running the latest version.

Gadwin Printscreen — good program for grabbing parts of the screen for making documentation. Also, if your mouse cursor is visible, it will be captured as well. That can be handy. There is a pro version, but the free version does all that I need.  (Direct download link for free version.)

Syncback (free edition) — Good basic backup program. I used to use it to back up source code files to my web host through FTP. Now I use it to back up my (home) file server every day.

Fiddler 2 — Not sure if your headers are looking correct? This web debugging tool can help. Works in IE and FireFox and others as well.

Stylizer Basic — This CSS editor is unique and very cool. The free basic version is really crippled, but you get a trial period with full functionality. I’ll actually probably buy the full version.

Image via Wikipedia

OpenOffice.Org (for PDF documentation creation) — Since compiled help files (.CHM) seem to have fallen out of favor, I do my online help as PDF files these days. OpenOffice.Org Writer is great for this. In fact, you can even create PDFs with forms that can be filled out. No need to buy Adobe Acrobat.

Developer Xpress CodeRush Xpress — According to their web site: CodeRush Xpress is freely available to all Visual Studio 2008 developers and offers a comprehensive suite of tools that enable you and your team to simplify and shape complex code – making it easier to read and less costly to maintain.

SSMS Tools – an Add-In (Add-On) for Microsoft SQL Server Management Studio and Microsoft SQL Server Management Studio Express.

What free tools have you found? Post comments below.