Mindjet's desktop app is one of the richest, most powerful mind-mapping tools I've seen.  Their mobile effort, Mindjet for iPhone, isn't half bad, squeezing a healthy dose of capabilities and excellent usability that should satisfy most professional users.

There's nothing complicated about what it does: the app lets you perform various operations for your mind maps. The big deal here is, you've got it on your phone, so inspiration can strike anywhere and you can immediately put it down without skipping a beat.

Upon opening, it takes you a map management screen, where you can create, edit and rearrange maps (up to 100x the handset's screen size) stored on your iPhone.  Creating and editing is very intuitive - double-taps on any level lets you edit the node, change various properties (like shape and color) and add a variety of details (including remarks, dates and completion percentages).  It works exactly how you'd expect it to on a small, multi-touch display, which is fantastic.

Uploading and downloading of maps to your computer is also possible, although this led to some amount of confusion on my part.  The process is not straightforward, requiring you to go through a web service to be able to share files between your devices.  If you encounter an error, make sure to check that files have an OPML extension (not XML).  Simple renaming works.

Overall, Mindjet for iPhone is a very useful mind-mapping application (with a look similar to iThoughts).  It's nowhere near as robust as the desktop counterpart, but for simple creation and editing needs, this is great.  Pricing is a little over the top, though, at $7.99.

[Mindjet]