It depends on resident status.
Tourist its a fine, although I now here that it is possible for EU countries to enforce acc borders, if not now, it will be coming in 2012 with the new updated license scheme.
Which means a traffic offense in Spain removing 4 points would then be transferred to the UK and 4 points added.
If your a resident then you need to register your license, have the first initial medical and then every in 10 yrs you need a Spanish license.
Without the initial medical, registration of your UK license, which is invalid in Spain as your no longer a UK resident, it`ll be taken from you, you`ll then need a Spanish one, which will then have the required points removed.
For using your mobile you`ll get 3 points removed.
This is a good reference of the rules, note though it does say after 6 months residency your license becomes invalid, this seems to be a general misnomer in Spain. Which is why its wise to exchange straight away.
http://fetcm.ugt.org/pdf_Nuevos/actualidad/en_profundidad/conductores_extranjeros.pdf
The link is too a pdf document from the UGT union, which is a major organisation in Spain.