Software offers the security necessary for mobile workers, and is compatible with BlackBerry, iPhone, and Windows Mobile smartphones.
Even without its workarounds for the iPhone's push data limitations, BeejiveIM is a pretty good multi-network IM client.
SHAPE's IM+ provides a way to receive instant messages when the iPhone's busy doing something else, but it does so in a barebones setting.
Don't panic when someone sends you an SMS, instant or e-mail message that seems to be written in a foreign language. This list will help you decipher the lingo so you'll know you asp from your EMA.
