I would like to access MSN account access in application.
How to do this?
Please suggest; can I get the web services from MSN?
Your question is a bit vague, however I will still try to answer. At the moment the only API I know that provides access to Windows Live services using Objective C is that of the Live SDK for iOS
The Live SDK for iOS library is intended to help developers to easily integrate SkyDrive and Hotmail contacts and calendars into their iOS apps.
The repository here includes:
Live SDK Library source (src/LiveSDK/Library) Live SDK framework (bin/LiveSDK.framework.zip) Samples (src/samples)
You can acquire documentation and additional help from Live Connect Developer Center.