Really Simple Syndication (RSS) is an XML-based format for content distribution. Any search you do on Nestseekers can be subscribed to as an RSS feed. This will give you up to the minute updates of listings in the neighborhoods you want, with the prices you want.
To access RSS feeds, you will wish to install a feed reader. After installing the feed reader, you can add each feed manually by clicking on the "XML" orange button next to the feed.