Hi Skorpio
1. Closest site to the action is Chapelle, but this is an open area that that all the general public stroll through so in my humble opinion not that great. Therefore Maison Blanche (although probably the first to sell out) and Tetre Rouge are closest. Apart from Beausejour which is a good mile and some more from the main viewing areas (although it is near the Porsche Curves) most of the sites aren't too far from the action.
2. A campsite ticket is approx. 35 Euros. This allows in one vehicle to the campsite, together with it's inhabitants plus as many tents etc as you have. Apart from Camping Houx where you have an allocated, numbered pitch, all the other sites are first come first served. You will also need a General Admission ticket for each person. These are availabl on the gate for 57 Euros each. You can buy them in advance if you want but but they are the same price, unless you are booking 20 or more. Please bear in mind that these ar 2003 prices that I am quoting so subject to change for 2004.
3. As Wishywashyman has already said, contact the ACO to book your tickets now. You might already be too late to get immediate confirmation but you should get on the waiting list and then get notified by them nearer the time that you have tickets. Otherwise, there are normally lots of excess tickets for sale on this forum in the weeks coming up to the race, all at face value (we're a friendly bunch!!)
4. You can arrive on the Monday or Tuesday prior to the race, but they charge you an extra fee for the early days. I believe thios year was the frst time they introduced this and the extra fee was something like 7 Euros per day per vehicle.
Hope this helps, any other questions just put another post up.