People far better than me are still working on disassembling all the Sinclair ROMs. So here are three links to the most important sites.
Paul Farrows site at http://www.fruitcake.plus.com/ contains disassemblies for the Spectrum 128, the Spectrum +2 and the Spanish Spectrum 128.
Most of the early ROMs (plus Interface 1 etc.) can be found on Geoff Wearmouths site at http://www.wearmouth.demon.co.uk/.
And the Spectrum 128K ROMs, now including the +2 ROMs, including French and Spanish versions can be found on Matthew Wilsons site at http://www.matthew-wilson.net/.
My thanks to Andrew Owen, Matthew Wilson, Geoff Wearmouth, Rui Tunes, Paul Farrow for their continued efforts.