For mine, the true gold in Soccer Nostalgia are the Full Magazines and Match Programmes blogs. Well worth seeking out via the menus.
Here's a quick sample:
Some of the pictures in the 1960's French magazines (like Miroir du Football, and Football Magazine) are truly exceptional.
Along the lines of what Paul Mavroudis and South of the Border have done, but going back a lot further in time, is the Northern Ireland's Footballing Greats blog. It has some real vintage annuals, guides and yearbooks that can be downloaded from here.
It would be great if our governing bodies could supply us with the means to do similar, but sadly it appears any such documents going back that far have been lost in the mists of time.
Miles McClagan's flickr album is another amazing treasure trove of programmes and magazines. It's the kind of site you can get lost for days in.
Football Programme Covers is another brilliant flickr collection.
There are several club-based sites with programme cover collections, including Tottenham Hotspur, Wrexham, Leeds United and West Ham United.
Feel free to provide similar links in the comments section below.