OK, this site is great http://www.backpackit.com , the basic free features are just what I need.
I was trying the TADALIST a few months ago, by the same creators of Backpackit, but I quickly gave up because there was no advanced options at all (like categorising to-dos, emailing..).
Let's see if I will keep using it in the future but so far I have created my long list of To-do for our new flat refurbishment categorised by room with a few links to the right shops, and I use the "Sharing" feature to share this list with my partner so he can update it/ add items to the list as we go.
We both use our Pocket PC XDA Mini-S (Wizard) with lots of To-Dos but were looking for a way to share the To-do. My idea is not to duplicate the to-do (one on Backpackit, the same on Pocket PC) but more to have the full list on Backpackit and write the ones of this week on our pocket pc.
By looking at Backpackit I realised that it's trying to use the concept of many books written about "GTD" Get Things Done, so I have to do more reading about this and apply it to my life/tasks organisation cause I don't find it optimal yet.