We have been in Malaga last november and had a free shuttle to the city. Its not in walking distance, because they docked in the industrial part of the port.
But getting of the shuttle you can explore the city on a walking tour. Here a part from my review:
After having a private walking tour in the center of Malaga, we took a taxi back to the ship. Cost was 6 Euros (7,20 $) Remark: there were almost no english speaking taxidrivers, in spite of the fact that we were asking for them. So communication was very difficult and I had to use my small knowledge of spanish.
You can find the whole review on our website:
and then the link Atlantik 2005 (also an english version)