Hi Neil, when we left America in 2008, I had my Blackberry with T-Mobile global mobile access. It was brilliant. I would compose emails while on passage and send as soon as we got close to shore throughout the Atlantic - Ireland, UK, Spain, Portugal, the Atlantic islands, Caribbean. It was truly the only global mobile service, and I do lament the passing of my trusted BB. Sigh.

Vice Commodore, OCC 

Currently the best Internet access for cruising that we have found is a Samsung V 100 T mobile hot spot. It allows up to 10 computers to connect with WiFi

With an American T-Mobile SIM card in it for US$30/month we have 5 Gb of data per month in 100 countries .
In many European countries it is rather slow, but plenty good enough for Email and modest web browsing. We have used is fairly successfully with Skype (voice only). When we bought it, the only source we could find was T-Mobile in the US. We have used it in US, across Canada, Norway, Italy, Spain and the UK.

If in one country only, then buying a local SIM card is a better deal, but that is a hassle when sailing to several countries (or rather Cellphone areas. We find that even the British Isles has 4 cellphone areas, and moving out of one incurs abusively high data roaming charges)