To initiate a phone call: Give us a call!
To initiate an SMS:
Send us a text!
Though you can also send to multiple recipients:
Send all of us a txt!
Standard input type (for comparison to the below):
Email input type (generic to HTML5, but perhaps most useful for mobile):
URL input type (generic to HTML5, but perhaps most useful for mobile):
Also check out the head tag in the source to see some iPhone-specific tags!
Try to select this sentence.