I just did this and it worked for me...
Go to
https://secure.spanningsync.com/osx/3/getcals in your browser. It should say can't verify certificate or some such. Click 'view certificate', then 'trust certificate' - you can open up the window by clicking a triangle on the left and you get a bigger window with three drop downs where you can also select 'always'
Then click OK.
I was then able to go back to the preferences for Spanning Sync and sign in where I couldn't before, and I've just done a sync of contacts and diaries with no problems. However it tells ME that SS will expire in 11 days (which is relative to when I paid my last year's subscription.
This is disappointing as I kind of thought that although they have decided to can SS it would be left to carry on running for those of us for whom it is still working - which I guess is those of us still running 10.6.8.
They do say on
ss.com that they have ended all new purchases AND RENEWALS but hey! it wouldn't hurt to keep it going for us would it?????
I'm at a loss as to how to proceed - I currently use Address Book and Contactizer Pro with Google calendars because I have an Android phone. I installed Lion on a partition, but a) Address Book in Lion is crap as it looks like a Filofax and the page won't expand beyond a fixed size so I can't see all my notes and comments and b) when I went to import my contacts to AB (Lion) from an AB Archive (Leopard) to get them up to the iCloud nonsense it mysteriously decided to only important some of them and truncate others, rendering it even more useless. Contactizer Pro currently works OK writing Calendar entries to iCal 'On My Mac' so that SS can sync them to Google, and SS also syncs a 'My Phone' only group of 350/5000 contacts to Google too, but Apple seem to have removed the ability of every other programme including there own to be able to write to Google Calendars - they can only subscribe and view - or Contacts.
Apple are obviously trying to force us to use everything Apple, but until they get better than Android - and also as cheap to have one - that's not a serious option!