To ease the development process of SharePoint web parts there is a simple way to automatically deploy those.
The following batch file assumes that you are deploying to the GAC directly.
Create this batch file called deploy.bat:
rem Pass these parameters: $(ProjectDir) $(TargetName)
rem Copy the assemblies to GAC
gacutil.exe -I %1\bin\Debug\%2.dll
rem Restart the application pool
cscript.exe c:\windows\system32\iisapp.vbs /a "[App Pool Name]" /r
Add the following entry to your post-build event command line in the project’s property window:
[path to batch file]\deploy.bat $(ProjectDir) $(TargetName)