WSS also has auditing
support allthough it is not possible to activate it using the user
interface. You can enable auditing using the next code sample from
within an feature activation callout.
SPSite sitecollection = properties.Features.Parent as SPSite;
sitecollection.Audit.AuditFlags = SPAuditMaskType.All;
For more info take a look at http://msdn2.microsoft.com/en-us/library/bb397403.aspx