Aeroweather is a nice app, put in the airports near you and get their data.
underground site (thru mobile safari) is decent especially if you bookmark the iPhone
specific url - i.wund.com
Radarscope is a solid application that uses very little bandwidth, so even on a slow link you can pull the data.
Ayetides seems to be the best tide program in my opinion.
I bought iNavx
when it first came out. Now it is just taking space on my phone
, the Navionics
app is superior in my opinion at this version at least, not sure what an update will do.
Walkscore is an interesting application for when you visit a new port, allows you to see whats near you from a walking angle.
Ideco is great if you are diver, even allows stage and deco diving
app can also have some applicability when evaluating a harbor, or anchorage.
and of course for entertainment - tradewinds 2, so you can pillage the Caribbean