Our server's four dual core processors were averaging 99.73% for a couple of days. After monitoring the situation with SQL Server 2005 Performance Dashboard Reports and implementing the suggested performance enhancements, our server's CPUs are now working at between 12% and 60%.
More about Microsoft SQL Server 2005 Performance Dashboard Reports:
"The Microsoft SQL Server 2005 Performance Dashboard Reports are used to monitor and resolve performance problems on your SQL Server 2005 database server."
"The information captured in the reports is retrieved from SQL Server's dynamic management views. There is no additional tracing or data capture required, which means the information is always available and this is a very inexpensive means of monitoring your server."
Download it here.