Startcli is part of the logon script executed whenever a user logs on. It uses the following parameters:
/s Specifies the name of the Small Business Server.
/u Specifies the name of the user.
/l Specifies the name and location of the log file.
Startcli.exe is basically used to install software on the client machines.
More information can be found athttp://www.microsoft.com/TechNet/sbs/technote/client.asp under the Client Setup Section. And athttp://www.microsoft.com/TechNet/sbs/reskit/sbs45res/part4/sbrk0425.asp under the Startcli.exe section.