They have a Domain Protect feature that is being applied to all domains registered with them starting October 18. I received their email not too long ago and haven't gone to see if there is an extra fee for this or not, but it closes the ICANN loophole for Network Solutions clients.

This is how they describe it:
To further enhance the security of the domain names you have registered with Network Solutions and to protect you against unauthorized or fraudulent transfers, we will activate our free Domain Protect service for all of your domain names beginning October 18, 2004.

Our Domain Protect feature blocks domain name transfers until you, or your designated contact, turn the feature "Off." This step allows you to control the "transferability" of your domain names, and provides protection against "domain hijackers."
Just something to think about. I'm sure 99% of the domains out there will never get hijacked, but it would really suck to be one of the few.