Yeah, the Morrissey's Manchester book will see you pretty good. Do be careful, though, as it goes into some pretty rough areas. Shouldn't be a problem as long as you're sensible (visiting during the day, not behaving too much like a tourist etc. etc.).
In terms of shops, I wouldn't say there was anywhere with an absolutely great range of Morrissey/Smiths stuff. Vinyl Exchange on Oldham Street get some nice second hand vinyl in at reasonable-ish prices and further up Oldham Street and just off it (don't know the street name) is Vinyl Revival which also has some reasonable stuff in from time to time.
Having had a few weeks of an uncharacteristic hot spell, Manchester is currently back to its customary summer fare of rain and gloom, so your experience should be suitably 'Morrissey-an', lol. Have a great time and let us know how you find it. Where you travelling from?
