Hello,
Some of the Internet Providers in Venezuela are: CANTV, MOVISTAR, DIGITEL, and MOVILNET (which also belongs to the first). Costs depend on the carrier and plans.
Concerning to Mobile Plans, the providers are the same as for the Internet Services. I'm personally suscribed to DIGITEL Mobile plans, and ABA Internet services from CANTV. DIGITEL Mobile Plans are the best out in the Market, they have a good relation cost-services. Any of the Providers may be found at most Malls around Caracas, and most cities.
As for the International Call is related, I'd suggest pre-paid cards, Skype, and even the call centers around the whole city.
I hope this information is in any way helpful for you guys! 