I researched on-line courses and Rocket Italian got the best rating.

It is self paced (I use downloaded recordings then go back to the on-line text and grammar) and I have found it very easy to learn quite sophisticated (but I realise still "baby" language) phrases.

Coupled with a trip to Italy you get a really good accent.
I really recommend it as it is also quite inexpensive and I have so far nearly completed the second premium course in about a year using it on and off.