What programs are best for learning a new language?

Rosetta Stone gets pretty good reviews.

Then again, if cost is not an issue, consider spending some time in Italy.

To start, I would download some Pimsleur audio lessons from a torrent site, or download some stuff from here: http://fsi-language-courses.org/Content.php

Use Anki daily to expand your vocabulary. It’s great.
It’s freeware and a lot of people use it, so there’s plenty of learning material to be found.

this website is more like a class room… which may or may not work for you… but there is a free trial to find out!
https://www.livemocha.com/users/login?redir=%252Fcontent%252Fcourse_home%252F1021

I second Pimsleur. It’s not a program per se, it’s on cds with accompanying booklets. I ripped a bunch off my local library.

Rosetta Stone or you can teach yourself by Google Translate.

As @bob_ said, going to Italy is the best “program” for learning Italian.
Immersion works so well. Besides living there when I wasn’t even a year old and couldn’t even comprehend 1+1 I spent two weeks there when I was in about fifth grade and felt like I was basically talking the language after a few days. Even when I am with my mom’s family who all speak Italian very religiously pun not intended, I feel like I learn so much. The one down side is that I think you may want to look a little more into studying the basics as well because with immersion, you sometimes loose track of using correct grammar, like conjugations, or even correct pronunciation of things, because sometimes a word just isn’t found in the common lexicon of the community and on a local newspaper.
sorry if this wasn’t too helpful…I thought that it was better than nothing, as deleting all of it seemed to be a big waste :)

@pshizzle but Google translate is grammatically wrong often and also subject to blunders. Just try translating a sentence to a language, say Italian, then translating it back. It probably won’t be quite right the first time back. Do it a couple of times and it degrades completely.

It is enough for limited flickr/fb/etc communication but everyone can tell you are using a translator.

If money is no object, then I agree that full immersion by going to Italy is absolutely the best way. Next, IMO, is Rosetta Stone, but many people reading this might find it too expensive. Also, check out local courses in your community. For example, in San Francisco the Italingua institute gives Italian classes. For Greek, many Greek Orthodox churches offer language programs, etc. Also, check out your community college or university extension if you have one in your community.
I find that Pimsleur is OK but not as good as Rosetta, but as someone else said, you can often check these out from your local library.
A little-known series that I find excellent if you’re just getting started is the “Teach Yourself… ” series published in the UK. The titles are all like Teach Yourself Beginner’s Turkish, Teach Yourself Conversational Greek, Teach Yourself Italian, etc. It comes in a booklet with CDs, or you can get the booklet and the CDs separately, but I think the CDs are worthless without the booklet and vice versa.
Berlitz also publishes something similar (booklet plus CDs), but I don’t find them to be anywhere nearly as good. In fact, their Turkish one contains many mistakes and the CD is almost impossible to follow. Stay away from the Berlitz.

Oh, I almost forgot. As @MaekoPoisoning said, LiveMocha is another good option. And there’s also Mango: www.mangolanguages.com

And another one that I almost forgot about… www.lingq.com This one isn’t free, though.

https://www.pimsleurapproach.com/search225/learn-a-language.asp?sid=001exPimCBT225_ggl&Network=Search&kw=pimsleur%20approach&ad=7290787865&SiteTarget=&s_kwcid=TC%7C3792%7Cpimsleur%20approach%7C%7CS%7C%7C7290787865&gclid=CJSbmPDSlrACFYic7Qodw2ok1Q

I know it sounds a little corny, but the first eight lessons are only ten bucks and it does work. :)