Karin,
Although I don't have an iPad (yet) I do have an iPod Touch (mini iPad) I've used for about two years to make occasional trades, including futures at 3AM! I've used platforms and data from Schwab and Interactive Brokers, the latter is my favorite, and I use StockCharts during market hours, when I'm away from my trading desk.
Interactive Brokers has a nice App in the Store. I also sometimes email myself charts from QuoteTracker that I store in Dropbox. Many things are possible for a trader using an iPT, and it can only get better with an iPad. . .faster, larger screen, better battery, and 3G.
Check out some market related Apps on an iPad at an Apple Store.
There's a huge future for the iPad and similar devices. I think it's a big tech step forward.
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