You have Telepac (http://www.telepac.pt) or Clix (http://www.clix.pt) which are ISP´s that provide a dial-up number everywhere.

In most hotels you can access either through a LAN with an RG-45 cable or through Wi-FI access. For wi-Fi try http://www.sapo.pt

For mobile phone companies please see http://www.vodafone.pt or http://www.optimus.pt or http://www.tmn.pt

Best regards, João in Lisboa, Portugal