The tune presently known as the Nokia theme...

...is, in fact, a composition by the Spanish composer Francisco Tarrega (1852 -1909). According to Wikipedia:

He is also the composer of what has been claimed to be "probably the world's most heard tune": the Nokia ringtone Nokia tune or simply Nokia, also used in their advertising spots, is based on Tárrega's Gran Vals.

Who'd a thunk it?

(Learnt this from the 'new' BBC4 panelshow, Face the Music 2007 which also featured Rory Bremner's version of 'I am very model of a modern Major General' as sung by our new Prime Minister.)