PubMed produces a mobile-friendly version of their website at:
A number of different PubMed iPhone and Android apps produced by independent developers exist as well. Some of them are free, and some cost money to download.
One free example of such an app is "Pub Med Tap Lite" for the iPhone/iPad. It searches PubMed for articles and displays 10 results for you, with links to full-text if available. It likewise allows you to enter your university's "EZ Proxy" information, so that if your university has full-text access to an article in PubMed, you will see a clearly displayed link to the material.
The upgraded, non-free version of the app presumably allows you to access more than 10 articles per search, and provides you with other useful features.