+1 Gates.
However, before you go rushing to Ebay, try the main dealer, especially if buying the whole timing kit (usually belt, tensioner, idler and w. pump).
I assumed that a Gates kit would be cheaper. When I rang my local Fiat dealer to check prices, I was really surprised at how affordable a kit was for my 2004 Scudo van. £85 all in.
Poss made by the same people anyway, but took the gamble out of it. Not sure how much extra confidence having Fiat printed on the boxes gives, but felt happier fitting the genuine, approved parts.
I believe Dayco are supposed to be OK too.