Yes
The Twitter App for the Blackberry is free.
download it from blackberry app world then use it :)
yes with the free facebook app or you can use safari.
I use my iPod, and I do not have a Facebook. It is a free app, and you can use your smartphone as well.
no. blackberry messenger is not free on o2. you must change your tariff to a blackberry bolt on tariff to use blackberry messenger. i currently have a bolt on which costs £5 a month for 500mb of internet and blackberry messanger and blackberry app world.
you must get the free app in the app store. the facebook app has "chat" but the myspace app does not have IM. to IM on myspace you must go to safari and actually type it in.
The messenger app is already in facebook, you can use it if you want to.
If you have an iPod touch then yes. Download the (free) Facebook app, or just use the Internet( whichever you prefer. )
Yes almost all apps are free however some app may have optional payment for upgrades inside the app
Yes
Get the app
No not really. Messenger is an independent app, you can work with it even when you dont have facebook app.