Looking to find an equivalent to Commission Junction or Linkshare
affiliate networks for non-US users/traffic.

More details:
If I own a Brazilian-targeted web site that gets traffic and I'd like
to promote various appropriate offers, is there an affiliate network
company that is Brazilian or specializes in offers for South American
people?

Hi, not sure if it answers your question but, no, I don't know any
brazilian company that acts like Commission Junction, where you can
offer your product.

Local companies prefer to develop their own affiliate program. If you
are interested you may find good examples on: MercadoLivre [1],
Arremate[2], Submarino[3], Buscape[4].

[1]- http://www.mercadolibre.com is an ebay-like site. They pay you R$
7 for each new account from your referrals and like 1% from what is
bought through your referrals' id. They are present on  9 countries in
LA (Mexico included). Ebay owns 25% of Mercadolivre.com
Link to ML's affiliate program:
http://www.mercadolivre.com.br/org-img/html/MLB/mercadosocios.html
Also, they have an API for developers.

[2]- http://www.arremate.com Yet another auction site. Almost same
values from MercadoLibre.com
http://www.afiliadosarremate.com.br/home/home_sl.asp

[3]- http://www.submarino.com.br - The biggest online shopping in Brazil. 
http://afiliados.submarino.com.br/affiliates/default.asp
Not sure how much they pay.

[4]- http://www.buscape.com.br - Buscape is a Froogle like site.
Number 1 in price comparison in Brazil and other countries in LA. They
pay for valid clicks coming from your site. (like R$ 0,10)

Unfortunately they all pay in local currency, in my case R$ (Brazilian
Reais) with direct deposit, not sure how it could fit for you.

IMO, Mercadolibre.com is the best affiliate program, it's my choice on my websites.