Menu will not wrap and will stay centred. Menu item widths are fluid.
works in ie5.5, ie6 and most other modern browsers. (ie5 and ie5 mac work but are not perfect)
Note that opera doesn't seem to honour fractions of percentages so 12.5% would be rounded down to 12%!!
Therefore the number of items must divide by 100% exactly.
Unfortunately ie needs a min-width expression to hold it all together.