If you know one Romance language, the others will be easy...but I've found that to be only partly true. I'm fluent in French. I've dabbled in Italian and Spanish, and I put in a good effort with Portuguese several years ago. Now I'm working on Spanish again, and I'm finding that I must have retained alot more of the Portuguese than I thought.

When I get going fast, French comes out.

I like Rosetta Stone alot, but I'm not stuck in front of a computer all day since I work from home and can easily distract myself (too easily sometimes)