Mulitple Internet Connection Issue

[Aaron O'Hara]

Up here in British Columbia, Canada the major ISPs (telco and cable
company) have started to enforce caps on bandwidth consumption per
month.  Other smaller ISPs have sprung out of the woodwork and offer
'unlimited' consumption but the problem is that the quality of their
connection is noticeably inferior to that of the major ISPs.

In what way could I configure Linux (I'm running FC3) so that it would:

1. utilize both connections to get maximum speed (until the cap is
reached on the 1 interface)

2. When one connection goes down, use the other (regardless of cap
situation with other ISP).  If this isn't possible, no big deal, but it
would be nice.

3. Implement traffic shaping so I can prioritize certain ports & PCs.
(I already have this setup, but I want to make sure that a solution that
allows for load balancing doesn't interfere).

I have read through the Linux Advanced Routing & Traffic Control HOWTO
and seen the section on Load Balancing, but it does not cover shutting
down one interface once a cap is reached.

Thanks,

--- Aaron