with "pure" batch commands and without external tools:
wmic /NODE:Server /USER:user /PASSWORD:pass process call create "command parameters","c:\workdir"
Although WMIC
is not available for Windows XP home editions (but WMI classes are available so you can use C# queries).
It uses WIN32_PROCESS class .Here how it can be used with C# . More C#\WMI examples
From vista and above you have also WINRS command (may is possible to used with XP also with some resource kits):
winrs -r:myserver command /domain:testdomain /userd:user /password:pass
You can also check XCMD which in some cases works better than the PsExec.