I have been requested to provide an XML feed for Sitecore items, as for example an XML feed for News section, All the fields should be provided using this XML Feeds, I wonder if I can do this using Sitecore.Services.Client? Or if there is a better way to serve this.
Frankly, if you're looking to produce an RSS or ATOM style document, I would use Sitecore's Presentation Device strategy and create an RSS layout of the root page of your News section (for example). In this way you can either render the children (or some sort of query) out as RSS in extremely easy fashion. The "distributable" URL for your RSS feed would include device=rss or something. 'Been doing it that way for as long as Sitecore and RSS have existed together.
You can assign a Controller Rendering as the Device's Layout and have it output the XML directly.
I would think of Sitecore.Services.Client as an API to use in conjunction with SPEAK apps, which however can be used for different purposes. You can also do that using the normal Asp.net MVC web API controllers (Sitecore.Services.Client is based on that).
As an option, you could go for Web Services or WCF, but that is likely an overkill for your case.