The goal with SQL Server is to not use the page file at all. If SQL needs to page data out then additional RAM should be installed as accessing data within the page file is typically as slow or slower then accessing it within the database files directly.
If you have SQL Server 2005 Enterprise Edition you can set the Lock Pages in memory setting to prevent SQL Server from using the page file, which is typically recommended. SQL Server 2005 Standard edition and below do not recognize this setting.
It’s currently recommended that you set your maximum memory setting for 75% of your physical memory. Another maximum memory setting is that you set the setting for 2-4 Gigs below your physical memory. You’ll need to try both settings and see which works better for you under your workload.