For one table you will need:
Four hook and eye strainers / turnbuckles as they are sometimes called. I used the smallest I could find, which are 14mm OD at the buckle and 5mm OD at the threads. Such as these from Screwfix
Four screw eyes and four screw hooks, of a gauge to match the turnbuckles.
Depending on the height of your bottles, you may need some ess hooks too to help the strainer reach between the upper and lower hooks.
Two pieces of reclaimed wood at least 25mm thick. Here I used some small pallets provided by the customer. Ensure the timber is rot free. Trim the boards square and to the dimensions required and sand to a smooth finish. If the board is constructed out of many pieces joined together, as in the example, ensure all joints are well secured as the board will be subjected to bending and shear forces.
Drill four holes and attach the hardware as described in the layout image (also in .pdf and sketchup format). I can not emphasise enough how great Forstner bits are for this job! (pictured).
NOTE: Andrea Biffi rightly points out that for stability is better that tensioners/turnbuckles are oblique (meaning, not vertical, they are meant to sit at an angle), as you can see in the attached drawings.
UPDATE 28/01/11: I have added some proper engineering drawings in .pdf format below. Also the source file packs in Solidworks 2004 and .stl formats.
Ensure that the screw eyes and screw hooks are securely held into the timber as they may be subjected to anticlockwise twisting - you may require pliers or a similar tool to fully screw in the hardware. If the timber does not allow a secure fixing, consider gluing in the fixings using a two part resin or using bolt through fixings.