Sending your updates to Twitter via your phone is free as far as Twitter goes but your standard plan rates for text messaging from your phone will apply. So, just like all of Twitter, anything you do on the site is free (as well as updating remotely or through third-party applications), but your individual data and messaging plans on your phone or carrier will still apply to each text update you send out.
You'll have to refer to your data/texting plan for more information regarding text messages. The updates are still a standard text message, so it'd be no different than sending out a text message.
For third party applications, you'd have to find out if the app will update via your devices internet access or via a pushed text message. Either way, you'll have to consult your carrier for charges incurred by texting or using data plans.
yes
yees
No
You need unlimited data for Twitter to be free.
nope! not at all if you have unlimited texting. just like you can text on AIM for free.
Yes you have to sign up.
Yes.
yes
Joining Twitter is free, using Twitter is free.
Yes. Twitter requires Internet access on your phone, therefore, it has nothing to do with your text limit. It depends if you have a plan that allows you to access Twitter for free. No it doesnt . if you're gonna send your tweets to 40404 , it dont requires internet access .
Yes, you can get an account on twitter.com.
Yes if you set up the texting service.
It depends on what data/texting plan you have.