Please could any one tell me if its is just a straight belt change or is there tensioners etc that need to be done also would you change the water pump? ps its N/A 2.8 ive had her nearly 5 years now i know it was done at 100000km there is a sticker on the rocker cover she now has 150000 many thanks johnny

100,000 Kms or 5 years is the recommended change interval.

Not done a 2.8 so don't know the answer to the other questions.

I've not done it...but looking at manual there is an adjustable untoothed idler tensioner....

Its a one peice timing belt cover....so I'd guess all the belts, fan and external pulleys need to come off to allow its removal.
Book says every 60,000 miles

I think the 3L engine repair manual was online at a hilux/surf site somewhere
I'd be inclined to put a new water pump on at the same time.....

The engine manual is 'toyota rm123e'
Quick search shows some ' torrents' ..but I'm not sure how to use them

2L, 3L engine repair manual here
If you click file..then save as...saves as pdf.
Strangely, this does'nt have the timing belt section as in the aug 88 version...(its a supplement)

http://www.toyota4wd.dk/Teknik/J70/Toyota%20Motor%20Manual%202Lt.pdf