re: Benny Lewis, I think he gives a lot of good (though hardly groundbreaking) tips for novice language learners, and his website's full of solid basic strategies to keep language learning stimulating and contextualised. But aside from his implied "if you're not fluent in 3 months you're doing it wrong" philosophy, I really dislike the entire notion of speed over quality.

Of course, nobody wants to be the type of learner who's an expert grammarian and has a huge vocabulary, but can't speak a sentence. However what about the opposite type? By rushing too quickly towards fluency you might learn to get your meaning across with all eloquence of a young child, but will probably peak at B1/B2 because you're constantly using the simplest words and grammar to get your meaning across. At that point it's very demotivating to go backwards and fill all the holes you left behind in your scramble to the top.

In any case, finding the right balance between study and use is important, but it's not as black and white as Benny Lewis claims.

As to whether we should speak the target language from Day1, my answer is a resounding yes. I am one of those who will not wait till I am ready.
We adults are not babies, and for one reason or another many of us can’t afford to sit through the quiet phase (1 ~ 2 years for infants). However, I think we should at least minimize the damaging effect by putting emphasis on certain abilities before others (i.e. listening before speaking as well as reading before writing.) By arming ourselves with the awareness of the danger of fossilization, I think, we will do a lot better.
In other words, I’d rather stand to be corrected then wait until I’m perfect. Knowing that I might never be perfect, I will just take the jalopy and fix it on the highway as I go.

Start speaking from day 1? Absolutely. You should get a strong grip on pronunciation (which necessarily includes the alphabet) before anything else to avoid fossilization of bad habits. That means you need to produce speech, so speak. 

But conversation from day 1? Only if you really want to torture a native speaker. There's no need to get to 1000 words + good grammar before talking; that smacks of avoidance. For me, good pronunciation/understanding of the alphabet, somewhere around 300 words, some basic grammar skills, a few dozen hours of listening, some basic reading and writing are enough to have under my belt when I start conversing. 

Thanks for the though-provoking comments everyone. But I think we need to take a step back and define "speaking practice" here...

If by speaking practice one means "voice chatting with another person", then I'm with overbyen: you'd probably bore the other person to tears, if you even managed to make it past two minutes. However text chatting is "quasi-speaking" (text chats offer a similar register of language to speaking in bite-sized chunks of everyday language), and fluency practice can be done in an isolated setting (don't worry, talking to yourself is only crazy if someone catches you doing it!).

One exercise I've done is to pick a topic, brainstorm some key vocabulary on that topic (10-15 words or so) and give myself 3 minutes to give an impromptu speech about it, using all the brainstormed words at least once. Then I try to say the roughly give the same speech thing in two minutes, with fewer pauses and false starts. Finally I try to distill it all into one minute (averaging one brainstormed word every 5 seconds or so, which ensures a wide range of vocabulary is being used).

Sometimes I'll record that one minute speech, play it back and transcribe everyting I said including the mistakes - this is good for finding areas of language I need to work on.

Anyway my point is that while real conversation is an unrealistic goal for quite some time, but we can slowly try to push ourselves out of the quiet period using focused exercises. The quiet period doesn't end abruptly, like turning on a light once you reach 1000 words.

When we're born we quickly learn that we can get someone's attention by making sounds, so is that verbal communication?

Then when we start to learn 'words', such as 'no, want, wawa (water)' we are communicating our desires and thoughts, albeit, in a rudimentary way.

I have visited several countries, and I always try to learn 20 or 30 expressions to show respect for their language.

They may laugh and smile at my pronunciation because it really does cute, but they always appreciate my efforts.

The point I'm trying to make is that we are rewarded and encouraged to learn a language when we have successes, however minor they may be.

So, yes, start talking ASAP... my opinion.