You can give public access to your wave by adding a user to your wave called easypublic@appspot.com.
(How it works: easypublic is a robot that adds the public@a.gwave.com which is the real public user)
If you are going to create many public waves, add the easypublic@appspot.com to your contacts list. You can then just drag the easypublic icon from your contacts onto your wave.
By making a wave public, everyone with a Google wave account can follow, edit, reply and add contacts to that wave.
Sending a direct link to a wave
You can tell people about your public wave by just sending them the web address -URL - at the top of your browser when viewing the wave.
(Note: the URL contains information about your Google Wave panels, whether they are minimised / maximised)
Searching for a wave
To find a public wave add a sutable tag to the wave: eg. skillsmatter and in the inbox search box, enter the following text:
with:public tag:skillsmatter
Once someone is following a wave, they can just use the search text:
tag:skillsmatter