Hi Jayne and Ray - the tapas trail is brilliant, the only problem for me is I have to drive home, so can´t partake fully of the drink bit!
If the system is the same as before, then there will be publicity leaflets available. I haven´t seen one yet but they do seem to publish things at the very last minute here. It should also be in the local free press, or in the tourist office.
There are no tickets, you simply go to the participating establishment and they will have two special tapas on sale - one modern and one traditional. It is a great way to try out new places that you have never even heard of before.
Enjoy!