Before I get into any actual project, can I access MS SQL in iOS?No.
What is the norm for apps to communication to a DB?The norm is to use a web service.
And can I just connect to my MS SQL?You cannot directly connect to MSSQL from iOS.
so my hypothetical database will sit on one of those sites for $5.99 per month...Eventually you will need a publicly accessible point to reach your code, but in the beginning you just need a PC on a network and your iphone on the same network.
And the iphone that is requesting the information... which part is that called?The iphone is going to call for example "http get" or just a simple URL (which till have a response you need to read) in fact once you have your WCF running you will be able to call the methods from firefox or safari and see the result it returns.
Will security be an issue, are these messages somehow encoded or is there any authentication layer?YES and YES and YES - but you are at the limit of my expertise there. I have never dealt with this issue.
And lastly, whatever I have to build on top of the server... a regular hosting site doesnt let you install anything else correct?I don t understand what your question is?
http://iphonedevsdk.com/forum/iphone-sdk-development/3942-retrieve-information-from-sql-server.html
you can access xml data from iphone