It was a short, strange road for Google Wave. Just a little over a year after being announced, the service was scrapped with little warning. While Google plans to use the Wave technologies elsewhere, wave.google.com is only going to be up through the end of the year. Google promised a way to get your existing Waves out, and now they've delivered on that.
Users will be able to export their waves as ZIP files. From within any wave, there will be a new option at the top called Export. Just click it, and choose ZIP, and select include attachments if you want. This will package up all the content in that Wave in one handy package. This works fine for people with only a few important Waves, but power users will find this tedious. Google claims to be working on a method for exporting ore content at once, but no details were given on that.
For most users, this should be enough. Few Wave early adopters used it enough to accumulate a wealth of data there. Are you exporting content from Wave? What sort of Waves are you keeping?