WebLantis.com has released a series of How-To videos of tradebit on the iPhone. I actually just downloaded and paid for it :->
The video tutorials are solid and give a very good start into the tradebit power section, which is - I admit - complicated to understand in some areas. Especially the underestimated discount groups and the collection building are a bit more complex to understand.
So, KUDOs to WebLantis, thanks for putting that into the AppStore: if you have your own website up and ready, let me know, so I can throw a link your way!
Also, on a side note: I just switched to iPhone4 on Friday and I really like it. The functionality did not jump up much, just some annoying mistakes (multi-tasking!) were killed on the first glance, but what I really like is the speed of that toy! It is like 5 times faster (guessing) than the old 3G model and the display is fantastic.