To sum up all your questions:

 1.  You don't even need a tv to have a workable slingbox - you just won't be able to watch the shows on anything else other than a computer in the location you phsycially have the slingbox.

 2.  You don't even need a computer at the same location as the slingbox - just initially to set it up.  After the slingbox is configured all you need is an internet connection (with a minimum of 256k up), a slingbox (configured), and either directly connect it to your DSL or cable modem or via a router (just be sure to forward port 5001 to the IP assigned to the slingbox if you use a router).

Now all you need is an internet connection that's worth a crap in S. America & a computer to get on it.