It looks like the rumours are coming to an end, a glitch on Apple's website today has all but confirmed the presence of the MacBook.
Earlier in the week it was rumoured that Apple Stores were receiving stock that was labelled "do not open until Tuesday, May 9th."
The long awaited MacBook has been rumoured since around November of last year, starting with the rumours that a future portable from Apple will include a 13" widescreen display, as time went by the rumour gained momentum and many rumour sites have speculated release dates with nothing but conjecture.
[Update] ThinkSecret is reporting that sources close to them believe that the new MacBook will be thinner than the current iBook, have a lower price and will be available in both black and white colours.