Does this help?
http://office.microsoft.com/assista...ID=HP010558681033&CTT=4&Origin=CH010427081033
"To start Project andType this switch
Specify the Project Server URL for enterprise projects ./s
For example:
/s "http://<ServerName>/projectserver"
Specify a user name of someone with permission to log on to the Project
Server specified in the /s command line option. This can be either a Windows
NT authenticated user account or a Project Server user account. /u
For example:
/u "ProjectServerUserName"
/u "domain\account"
Enter the password for the user specified in the /u command line option.
This is not required for users with a Windows NT authenticated user
account./p
For example:
/p "password"
Open a specific projectfilename
Display the Project Server Accounts dialog box-ProjectProfiles
Note If you don't provide the switches /u and /p, it's assumed that the
currently logged on user uses Windows authentication.
-Jack
"