I realised today that I'm still subscribed to Ancestry.com (I really ought to check my bank statements more often!) and then I found this site....another Download Squad honourable mention. At Kindo (registration required, it's an online app) you can collaborate on your family tree. It's private, in that only invited users can view and edit. But, having checked it out, it acts as more of a family contact/calendar site rather than as a proper genealogy application. Ancestry.com also has an online family tree maker that looks like it might be better, but you may have to be a subscriber to use it....maybe one of you could try it and let me know?
Tell you what, it's about time we got that yellowing roll of wallpaper out and had another go at the tree while I've still got access to the Census records....maybe we could double it up with a Roman Feast!!
LATER....I've had a play with the Ancestry.com Family Tree Builder and it looks like it's free to non subscribers, there's even a (home printable) Family History Book Builder to amuse yourself with.