Inserting XML data in sqlite database is no different that inserting any data. So there are 3 parts of the problem you are trying to solve:
- Calling the web service and getting the data
- Parsing the data and populating some object
- Inserting that data in sqlite database which has columns as per your object structure
NSURLConnection and NSXMLParser are the classed you need to look at for solving first 2 problems. Third one would be solved using sqlite library. Without more information about object structure it is difficult to suggest anything else. But you should find enough documentation on using sqlite if you search around.