The nature.com iPhone application

"The nature.com iPhone application allows you to access science news stories and the latest published research from Nature Publishing Group on your iPhone wherever you are. As new articles are published they're pushed straight to your iPhone where you can read the full text immediately or just save them for later. Tell the app which journals you're interested in or set up saved searches, which will show you the titles and abstracts of new articles from any journals in PubMed that match your key words."