Thank you for your replies. It seems that virtually any solution out in the market for remote access makes use of a Web server to provide the data tags to internet browsers. PeakHMI does just that. I don't want to put a dedicated PC on the PLC site if I can avoid it. Not that I dislike it but I am looking for a more straightforward solution, if available.
I just have a CJ1 omron PLC which I want to access through the mobile phone network, in the most direct way if possible. (It is a mini hydro plant which does not have a PC on site).
I looked again at ScadaMobile and it seems to do it all, no nothing between the phone and the PLC, except probably an ADSL or GPRS router. The interface is of an iPhone native app so it does not go through a WEB server either. The developers provide a link to a Google Group which states that the app will be released next month. So, I may give it a try when it is released if I don't find anything else in the mean time. More suggestions are appreciated though.