Bicycle Tutor

I need to replace the rear brake cable for my v-brakes because the end is frayed and it started fraying up the cable.
How do i go about installing the new cable?
And by the brake handle, where the cable housing goes into some metal thing... is it loose when you dont have the back tightened? ( housing doesn't stay in... when i pull lever it falls out of the metal thing its supposed to be in)

http://bicycletutor.com/adjust-v-brakes/
http://bicycletutor.com/replace-cable-housings/
Those two should probably cover it

Why when i go to put the noodle and boot on the rear brakes and tighten it up.... the housing bends the cable in an odd way and the brakes don't work properly? i mean the housings i used are the EXACT same as the when i had the old cable... so why is it only bunched up now?

I changed my gear cables and when I pulled out the old wire it must have been the straw that broke the camel's back. The housings became frayed and I had to buy new ones.
It's a generally good idea to replace housings with cables... does that answer your question?