Basically what the question asks. Have you ever used the computer based language software Rosetta Stone to learn Spanish or another Latin based language like French, Italian, or Portuguese? How long did you use it, did you complete all or most of the lessons/levels, and did it work for you?

If you've used it for another language like German or Dutch feel free to answer but I'm planning on using it for Spanish or one of the other major Romance languages.

It's not. It's derived from Germanic languages.
The romance languages (Portuguese, Spanish, Catalan, French, Italian, Romanian, Friulian, etc.) are derived from Latin, but not English.
English has words derived from Latin, but only because English speakers have a great habit of borrowing words from other languages.
Germanic languages are not derived from Latin, they are derived from the same languages as Latin, but they formed into two separate branches. I know Modern English (and really most modern languages) are a hodgepodge of influences. But I've noticed that people think English derived directly from the language of the Romans.

If I learned to speak Latin, would people from countries with Romance languages be able to understand me?

For example, if I spoke to a Spanish person in Latin would he understand me? I don't necessarily mean word for word, but enough to hold some kind of pseudo conversation?

I want to learn Latin in order to have the foundations to ease the learning of the romance languages. If I learn Latin though, I would obviously want to read some great works in Latin (or at least try, lol). So, is there a distinction? I ask because im under the impression that vulgar Latin is the root of the romance languages, but that it differs from written Latin. So...I want to learn Latin: Where do I start?

Basically what the question asks. Have you ever used the computer based language software Rosetta Stone to learn Spanish or another Latin based language like French, Italian, or Portuguese? How long did you use it, did you complete all or most of the lessons/levels, and did it work for you?

If you've used it for another language like German or Dutch feel free to answer but I'm planning on using it for Spanish or one of the other major Romance languages.

It's not. It's derived from Germanic languages.
The romance languages (Portuguese, Spanish, Catalan, French, Italian, Romanian, Friulian, etc.) are derived from Latin, but not English.
English has words derived from Latin, but only because English speakers have a great habit of borrowing words from other languages.
Germanic languages are not derived from Latin, they are derived from the same languages as Latin, but they formed into two separate branches. I know Modern English (and really most modern languages) are a hodgepodge of influences. But I've noticed that people think English derived directly from the language of the Romans.