Your 401k statement will provide more information and it will be mailed out more frequently.  

USAToday explains changes to 401k statements.

A little-noticed provision of the new pension law requires that traditional 401(k) account statements include, starting in 2007, advice about the need to diversify your portfolio and avoid loading up on your company's stock.

Employers and financial providers also will have to send 401(k) statements to employees every quarter, rather than annually, as some companies had done.