If you have not looked at this book for a while it might be worth digging it out and dusting it off as there are a number clues have been posted on the website:
1st Official Clue - December 23rd 2007
The solution to this puzzle is not directly logical as in some other Treasure Hunts but instead involves some lateral thinking
2nd Official Clue - February 3rd 2008
If you think you know where it is, you're probably right but the devil is in the detail
3rd Official Clue - March 30th 2008
Navigation, navigation, navigation - to find the token, the code must be broken
4th Official Clue - June 30th 2008
WriterianThe more you look, the more you see,
The more you see, the more you find
The more you find, the more you look
Been away on business and missed that.
New clue published today.
9th Official Clue - August 4th 2009
'The road ahead is full of signs,
are you thinking along the right lines?'
There are no Rules in the book and I can't see any on the Oracle website either regarding restrictions on participation.
According to the website, to claim the cash prize, you must locate the hidden token based on the clues within the book. The token has been hidden somewhere in the UK and instructions are included with the token how to claim the prize.
It is a nice book and an interesting hunt, however I don't think there are many people working on this hunt at all, at least the forum is very quiet. In fact it is probably about a year since I looked at it in any great depth. (Suprising really given that the prize currently stands at £5,000). So if the rules permit I'd say it was worth jumping into it.
Maybe I'll dig it out again when I've finished working on some of the others I'm dabbling with at the mo.
The puzzle creator is a forum user called Clearo, perhaps you could PM him re rules on participation or drop him a line via the queries page on the Oracle website.
The Oracle - Lost in Time
Hope that helps