Oldham borough is quite a big place with a wide variety of habitats, so it really depends where in Oldham you are going to be resident. I'm a firm believer in having a local "local patch" - somewhere you can explore even if you have only half an hour to spare, where you can observe the changes in the local bird populations throughout the changing seasons.
The only sites on this website are Castleshaw and Brun Clough reservoirs - but that's because only Mr Rigby has taken the time to compile them. Dove Stone is adequately documented by the RSPB website, but there are many other wonderful places which are either unexplored or unreported.
The one thing that the borough lacks is arable fields, and you won't be seeing many Yellow Wagtails, Corn Buntings or Tree Sparrows (to name but three species) round here. There again, you don't get many Red Grouse in Timperley!
And I think I'm right in saying that there's not a single bird hide in the area - you'll have to go out looking for birds and not sit and wait for them to land in front of you
Oh - don't forget that Saddleworth is actually part of Yorkshire (only part of Greater Manchester for bird recording purposes)