Newbie here, please be gentle. 
I've looked into many different GTD applications but ended up settling on gtd-php. You can view info at http://www.gtd-php.com
The app is free and is web-based, but you need to be able to install php applications on a web server. There are no companies that offer pre-packaged gtd-php services that I know of.
Anyway, it offers a lot that I was looking for (actions, next actions, contexts, projects) except for subtasks and a calendar, although I can list actions by due date. It just does't appear in calendar format. There are also things offered (visions, roles, values) that I may never use. One problem is that on the iPod Touch I can't access the menu list at the top of the page. I need to get to my lists using the links below it. That's annoying but I'm just glad I can view and modify using the mobile.
For anyone interested in more info the author has a demo page here:
http://www.youtube.com/user/gtdphp
Is anyone else using GTD-PHP? If so have you found a way to implement a calendar or subtasks? How about reminders?
If there is a *reliable* web-based service (one that won't disappear in 6 months) that is similar and has an iPhone counterpart I'd be happy to hear about it. I've looked into Omnifocus, Pocket Informant, Action Lists, ToodleDo, Remember The Milk, Dunnit, Evernote, Todo, and nozbe. None had everything that I wanted. Nozbe was close but I don't like the UI. ToodleDo is probably closest and I'm trying to learn to use it but I don't care for the UI. GTD-PHP is easy on my eyes. ToodleDo is not. heh

I've looked into many different GTD applications but ended up settling on gtd-php. You can view info at http://www.gtd-php.com
The app is free and is web-based, but you need to be able to install php applications on a web server. There are no companies that offer pre-packaged gtd-php services that I know of.
Anyway, it offers a lot that I was looking for (actions, next actions, contexts, projects) except for subtasks and a calendar, although I can list actions by due date. It just does't appear in calendar format. There are also things offered (visions, roles, values) that I may never use. One problem is that on the iPod Touch I can't access the menu list at the top of the page. I need to get to my lists using the links below it. That's annoying but I'm just glad I can view and modify using the mobile.
For anyone interested in more info the author has a demo page here:
http://www.youtube.com/user/gtdphp
Is anyone else using GTD-PHP? If so have you found a way to implement a calendar or subtasks? How about reminders?
If there is a *reliable* web-based service (one that won't disappear in 6 months) that is similar and has an iPhone counterpart I'd be happy to hear about it. I've looked into Omnifocus, Pocket Informant, Action Lists, ToodleDo, Remember The Milk, Dunnit, Evernote, Todo, and nozbe. None had everything that I wanted. Nozbe was close but I don't like the UI. ToodleDo is probably closest and I'm trying to learn to use it but I don't care for the UI. GTD-PHP is easy on my eyes. ToodleDo is not. heh