Operamini and Googlemaps. The two best FREE apps, IMO.

As far as chat clients go....I found this post by Mark Rejhon:

What Instant Messaging Software Is Available For BlackBerry?

BeeJive's JiveTalk (Multi Network) (One-Time Fee) (see review)
IM+ (Multi Network) (One-Time Fee)
RIM's Google Talk (Google Talk) (Free)
RIM's Yahoo Messenger (Yahoo) (Free)
RIM's Windows Messenger (MSN) (Free, only on some carriers)
RIM's AOL Instant Messenger (AIM) (Free, only on some carriers)
RIM's BlackBerry Messenger (PIN) (Free)
Yak-On (Multi Network) (One-Time Fee)
WebMessenger (Multi Network) (Annual Subscription)
Causerie Messenger (Multi Network) (Annual Subscription)
BerryVine Messenger (MSN Direct Connect) (One-Time Fee)
QuickIM Messenger (MSN Direct Connect) (One-Time Fee)
Ramble (AIM Direct Connect) (Freeware)
BlackChat ICQ (ICQ Direct Connect) (Free Open Source)
(Updated List: Click Here.)