Any publicly known services will provide you nothing as they are designed for provider income not accuracy, what you are looking for are high probability setups where you decide on the ultimate entry criteria. The principle is simple, 99% fail in the markets so you want an algo that eliminates 95%+ of the noise. Yes, a few exist but not entirely sure how you would get access to them. Know of one that matches your requirements but can't see what you would you bring to the table to make it worthwhile opening it publicly. Your theory makes sense but the practice is a long way off.
I would think you would prefer to use your broker or charting vendor mobile app for such ? Many charting vendors these days have mobile trading platforms for iPad, iPhone, android or whatever in which you can setup simple price alerts when the price action reaches the price alert. You can then decide to trade if you want via logging into the app and using the mobile trading platform. Yet, I don't know of any broker or chart vendor that will send a "twitter message"...never heard of such a service that sends alerts (price, stop hit, order filled or profit target) via tweet to your twitter account. I think I would prefer those that would send a "direct message" to my iPhone or Android instead of sending a message to my twitter account.
The really good entries seem to disappear really fast. I dont see how its possible to see an alert and then go and put your order in and still have good R/R. Maybe if you are swing trading.
I'll be posting my algo trading levels in the journal section under "Futures Trading Signals". This is a time tested algo used by a un-named hedge fund for 12 years. I trade it personally in real time with success for years. As a side note, I have been trading since 1989. It's not a holy grail, but it has served me well.