Yup.  If the trees are in containers (either pots or plastic cylinders) you can plant all year round.  Although I haven't used them, many people recommend someone at the Tortosa covered market (maybe outside) and this includes locals as well as ex-pats.  Estorach (directions supplied if required) are also an excellent source for all plants.
Ground preparation is important for good results but there's plenty of info on the net.
Feel free to pm me if you think I can be of any help.  I planted 92 olive trees about 5 years ago and have also planted quite a few fruit trees, both with varying degrees of success and I'm still learning.