You can add a robot named nortonwave to your contact list. And Add to the waves, where you want to check the links inside is safe or not.
To use this (same like the previous posts How to shorten links in a Google wave, How to add emoticons to Google wave, etc)
1. Add email@example.com to your contact list
2. Add Norton to the wave
3. When you finished typing a wave it will display an icon near to that link showing it is safe or not.
For more Google wave tips and help check here