TurboTax 2010 (Free, but has in-app purchases) Those who use TurboTax for their taxes can now do so via the iPad. The app itself is a free download, but like all of Intuit's products, filing the return will cost you. Those who have used TurboTax in the past will find the interface familiar. Filing returns starts at $29.99 for federal taxes and $36.99 for state.
Tax Central (Free): This app from H&R Block allows you to check your Federal return status. It also allows you to create checklists for doing your taxes and estimate your refund, and it provides access to a tax help center that allows you to look up questions, define tax terms and more. And, if you throw up your hands in defeat, the app will also provide directions to the closest H&R Block.
iDonatedIt ($2.99): iDonatedIt keeps track of all the random donations you make throughout the year so that you're not struggling to recall them when doing your taxes. The app tracks when and where you donate and the fair-market value of items you've donated, then generates a record that will comply with IRS requirements. You can also attach photos to the record and email them.
IRS2Go (Free): Finally, we have the app developed by the IRS itself. Like other apps, it will allow you to check refund statuses. You can sign up to get tax tips emailed to you, how to contact the IRS, and you can follow the IRS' Twitter feed from it. However, it does not provide access to tax code, forms or the sort of tools found in Tax Central. Still, if you feel more comfortable using the official app to check your refund status rather than Intuit or H&R Block, this app is not a bad way to go.