How do I use yahoo & Facebook with my mobile?

[750]

What if someone doesn't have a computer or is living somewhere for a vary long time without his/her computer.
If he/she wants to access his/her Facebook account & Yahoo account with his/her mobile, What should he/she do?
I mean how do I use yahoo & Facebook with my mobile?
I don't know how to do that & I don't know any trust worthy people who can help me (everyone I know is evil, pure evil).
And I wanted to know an other thing:
Suppose I'm using my mobile for accessing my yahoo & Facebook,so if someone enters my yahoo ID or Facebook ID with their computer will I be able to know that(like a massage arrives to my mobile/yahoo/ telling me that )?
Please I need to know these answers so please answer m & don't bother answering my question if you don't know the answers because I don't want any silly answers.
Oh please help me!!!

[Ralphie G]

If you have a smart phone. you can get an app! but you need 3g OR wifi!! IF you have a regular phone use google. or yahoo. Also, yes you will be able to know that so yes..

[Christian]

It depends on the phone, if you have a smartphone, there will be apps on the market for Facebook and yahoo. If you have a prepaid phone with a browser, you use that and go to Facebook.com using the browser on the prepaid, or yahoo.com. I have had a prepaid and smartphone, and had used Facebook and yahoo on both of these types of phones. I would recommend using a smartphone, and downloading the apps for Facebook and yahoo. In fact, as I answer this question, I am using a smartphone.