I just came back from Colombia and Peru two weeks ago.
The 09 Mobile did not work in either country. It registered (there were up to three networks available) but was for emergency purposes only or did not allow to dial out. People could not reach me either.
In Peru I used a German T-Mobile (around $ 3 for outgoing and $ 2 for incoming calls). I would recommend a local Claro SIM card which sells for 30 soles (US$ 10) which gives you free incoming calls.
In Colombia I bought a TIGO SIM card for 10,000 pesos (US$ 5.00) which gave me free incoming calls, messaging for about 50 cents to foreign numbers and reasonable rates to other TIGO subscribers. Calling out is very expensive and I cleaned out my account after less than a minute. Vouchers are available everywhere. Ther is a also Movistar. Best to go to their websites to check them out
www.tigo.com.co
The small print in the TIGO contract explicitly says that their networks cannot be used for call-backs etc and this is why very few foreign SIM cards work in Colombia.
The situation in Ecuador is similar. Last year I tried my T-Mobile and it did not work. A Peruvian Claro SIM card was of no use either.
Any quad phone should work.
Wolf