A new feature has just recently been added to MOBi Phonebook that I developed for our client (the owners of MOBi) for free in my spare time.
The reason for this is that I use MOBi myself a lot and I needed an easy way to export my contacts and later be able to import it again. So I used the Excel HTML solution and simply added a bit of formatting to it. It opens in right up in Excel (or like in my case, OpenOffice oocalc) which makes it damn easy to edit the contacts.
If you need to put this back into MOBi you have to save your spreadsheet as a comma separated CSV file. Fortunately that importing is pretty smart. It can add and update new data and everything it can't handle (conflicts) it shows you for manual editing.
This is not the first time I add things for free to clients. I do not want any compensation for it because I do it for a purpose. In the case of MOBi, I do it for me, myself and I. All I had to do was to check with the owners if they ok'ed it.