You can achive it by using business data list connector for sharepoint 2010, after downloading and installing it, try with the following steps,
1.Create your list in SharePoint, e.g. a custom list named XML. Tipp: Use an appropiate list type, e.g. contacts for address-based information etc.
2.Goto List Settings > General Settings > Connect to external data source. If you don't have this link, please activate the Business Data List Connector for the current site collection.
3.Select the Layer2 Data Provider for XML as connection provider.
4.Enter the following settings as Connection String: e.g. URL=http://www.w3schools.com/xml/cd_catalog.xml
alternatively you can use XML files, e.g. URL=C:\myfile.xml.
Validate the connection string.
5.Enter the following XPath settings as Select Statement:
e.g. select * from /CATALOG/CD[COUNTRY="USA"]
Validate the select statement. Preview your data. Take a look at the content: Are there unique columns to use as primary key? In this case Title and Artist should be unique together.
6.Enter the Primary Key, "Title, Artist" in this sample. The primary key allows to savely update items later on, in case your source data changes. Validate your primary key.
7.Klick on "Add Columns" to create the list structure for hosting the external data. Please check mapping. Mapping is done automatically by internal SharePoint column names and data source field names. You can change column titles and column types (e.g. currency) later on.
8.Klick update for first insert. Please note that this could take a while, depending on data amount and configuration. If done, click update again. It should be much faster, and there should be no changes (based on primary keys given).
9.You can now enter some final options about background update, e.g. scheduling etc. if required.
10.Don't forget to save your connection with "OK".
If you want to do it by code, you can create a console application as mentioned in the below link, create a windows task and execute the console application "exe' to update the list.
Console application populate SharePoint List from XML