It’s no secret: Give employees a computer, and they’ll always spend some time on non-work activities. But how can managers keep productivity problems from getting out of hand?

Some experts warn against using strict computer use policies, monitoring and Web site blocking  across the board — if employees feel like the boss is watching their every move, morale might drop and productivity could actually suffer.

Instead, many say managers’ time is better spent dealing with individual performance problems as they happen and helping those employees get back on track.

When managers do have an easily distracted employee, there is plenty of free or low-cost software available to keep the temptation to procrastinate in check and teach some self-discipline.

Here are some of the best free tools available, recommended by CNET columnist Josh Lowensohn:

• E-mail Discipline — An add-on for the Firefox browser that makes a user earn the right to goof off at work. It blocks a list of Web sites, including Facebook, YouTube and personal e-mail services, allowing access for only a short period every two hours — making the sure the user gets some work done before taking a break to visit those sites.
• MeeTimer — Another Firefox add-on, MeeTimer keeps track of how much time a user spends on different categories of sites throughout the day. Employees can see what percentage of the day they spend on work-related browsing, personal e-mail, social networking, etc. — and may change their bad habits once the data’s spelled out for them.
• RescueTime — Similar to MeeTimer, RescueTime measures how much of the day employees spend on different sites and computer programs. There’s a free individual version available, as well as a subscription-based business version that lets managers view the total data for an entire team.
• HassleMe — This service sends free e-mail reminders to users about important tasks they need to complete. It’s perfect for little things that need to be done every day or every week, but are easily forgotten amongst everything else employees have to do.