I just got my iPhone, and am on an app-downloading spree. Help me build my list of apps!
I'm marking this question as fun so that we can also include apps that aren't necessarily useful for IT people, but that IT people might enjoy. However, if it is more of a "fun" app, please mark your answer community wiki.
Also, here's the comparable question on stackoverflow.
Collecting into one big answer:
Cydia (lets you add loads more apps)
I have a dedicated page on my iPhone with useful applications:
Other apps not on the same page:
Here are a few I have on my device:
TouchTerm (SSH client)
I'll add to those:
Mocha VNC Lite is good.
However i did find even if the host is set to 800x600 my iPhone complains it is running low on memory... turning off 32-bit colour mode in the client seems to fix this.
My website is hosted with slicehost, so the Slicehost tool is excellent for starting, stopping my server, changing DNS settings and all sorts of other admin stuff.
NetPortal let's you browse file shares. I use it in combination with VPN to browse Windows shares at the office