Mild Winters, but can get chilly. It will take you longer than expected to get settled because there are many details to take care of. Don't expect to get a lot of work doen for the first month or two. Many people say that Barcelona is an expensive city, but compared to the US, it really isn't. The only thing that is expensive is hotel prices.
Food is cheap, transportation is good.
Phone can be expensive if you are on the Internet a lot. Try to learn a little Catalan while there.