I have a Shimano XTR component set on my mountain bike and I've been having some trouble getting the chain up on to the largest ring on the front sprocket of my bike (the crankset?). The crank sprocket contains three rings (I hope that's the correct terminology) and the derailleur can shift between the lower two rings just fine, but it just won't go out to the largest ring. I thought perhaps that the stops (terminology?) needed adjusting or the cable needed tightening, so I fiddled around with those and it never got any better. I gave up and took it into a local bike shop and they told me that may cable and stops were adjusted just finfe, but the shifter on my left handlebar (which controls the front derailleur) was shot. It just doesn't want to push the derailleur out to that final ring.
They then informed me that there is no hope in fixing it and that I needed to replace it because the shifer contains too many delicate parts (like a watch) and I couldn't get parts for it anyway because my components are so old (we purchased the bike, brand new in the late 90s). They then went on to explain that I would not be able to just purchase and replace that one shifter. They claimed that I need to replace the entire component set because I have a 9 ring rear cassette which is no longer supported in the XTR line, so I need to get new shifters, derailleurs, crank, cassette and brakes (the brake levers are built into the same module as the shifter).
When I balked at the four digit price tag they were dangling in front of me, they recommended I could replace the lever with an XT version and not have to replace any of the other gear. Does any of this make sense?
ffs go with option 2! 
I'm willing to bet XT these days is better than 90's XTR.
[url= http://www.chainreactioncycles.com/Models.aspx?ModelID=20701 ]http://www.chainreactioncycles.com/Models.aspx?ModelID=20701[/url]
You need a set of these if you have got a 3x9 speed set up. Might be able to shop around and find them a bit cheaper. They do a 10 speed version too, so make sure you get the right model for your drive train. M770 is the model number for 9 speed xt shifters.
Or if you just want the function you could save £20 and get slx.
A whole new groupset because of a broken shifter? They saw you coming.
If it is 9 speed then you will need new shifters yes. But what brakes are on it? I am guessing V brakes? Just get some individual V brakes and some new shifters.
OR just put a wanted add up for some XTR dual control shifters/brake levers. You should also be able to find XT dual control shifter/V brake levers.
Get some pics up and people might be able to identify your stuff.
a quick google: http://www.sjscycles.co.uk/9-speed-shimano-deore-xt-st-m770-dual-control-sti-levers-for-v-brakes-prod14335/?src=froogle
Someone probably has some lying around for a fraction of the price.
edit: just spotted the last line. This must be what they meant.
If you want to stick with XTR you can get LH shifters [url= http://www.chainreactioncycles.com/Models.aspx?ModelID=15184 ]here[/url], or just get a pair, the M970s are nicer than the M952s.
[url= http://www.chainreactioncycles.com/Models.aspx?ModelID=15193 ]Brake levers[/url] are totally unchanged from M950s, just new finish, again you can get a pair, or individually.
New shifter and brake lever for £100, sticking with XTR. Not so bad. Be sure to order 2 individual brake levers for £70, not the pair for £85, even at retail they're suggesting the pair is more expensive. Weird.