Bike boxes in Santiago

You could try these folks:

http://www.bicicletasoliveira.com/

EMBALAJE DE BICICLETAS
Servicio especial de embalaje
de la bicicleta en cajas para el
adecuado transporte en medios publicos.
PACKING OF BICYCLES Special service of packing of the bicycle in boxes for adapted transport in average public.

Click to expand...

I have just come back from Santiago, and I also used Velocipedo, Rua de San Pedro. They did a first class job on packing my bike. They took the bike including empty paniers, handle bar bag, cycling shoes and helmet etc. It was wrapped up in rubber, peddles off and handle bar turned and put into an old cycle box, 19 euros. They then gave it to a Taxi firm who picked me up from my hotel the next morning in time for the Ryanair flight.
There is an internet cafe at Rua da Senra near the park. Here you can book your return flights and print off your online check in.
I stayed at Hotel Entrecercas, Rua Entrecercas near the southern end of Rua do Franco. English bit iffy but better than my Spanish. Good Luck.

Just back from riding il Primitivo and I also used "Bicicletas Velocípedo" and they did a great job with the packing. I gave them the bike and a taxi picked me up the next day. They also speak English