Some e-mail services provide spam filtering, but perhaps the better approach is a spam-filtering service that also gives you an e-mail account. For $15.99 for six months, AlienCamel gives you a spam-filtered POP3 or IMAP mail account. And we found that AlienCamel's innovative, proprietary approach to spam filtering works fairly well.

At the core of the service are server-based whitelists and blacklists. Mail from users on your whitelist goes straight to your in-box. Mail from users on your blacklist goes to the Spam folder. Mail from other users is stored in a Pending folder, and you are notified by an e-mail (called the Pending Messages Advisory) that contains a list of those senders and the subject lines of the pending mail.

The Advisory is not just a message but an HTML form in which AlienCamel classifies each e-mail either as probably spam or probably not spam, using two different spam-filtering algorithms. For each pending message, you can whitelist the sender and accept the mail, blacklist the sender and send the mail to the spam folder, retrieve the mail without whitelisting, or reject the message without blacklisting.

We set up an IMAP account and used AlienCamel for almost a month. By the end, we were still seeing some spam listed as probably legitimate mail, but we hadn't seen a real message classified as spam in weeks.

We like that the Pending Messages Advisory interface let us filter spam without having to look at the actual messages, but sometimes the sender name and subject line can be ambiguous indicators of whether a message is spam. And there is no way to preview the message except by opening the Pending folder in your mail client.

The other problem, which may be a deal breaker for some users, is that AlienCamel works only with POP3 and IMAP software. If you want to use AOL or Web-based mail, you're out of luck. But since you can read POP3 mail into an AlienCamel account, you can continue to use an existing POP3 account.