There are lots of apps, both free and paid, that provide you with federal rules and other statutes on your iPhone, but LawStack is notable because it is a free and powerful app that contains in a single app all of the federal rules you are likely to need: the federal rules of civil procedure, criminal procedure, appellate procedure, evidence and bankruptcy plus the U.S. Constitution. LawStack was developed by Tekk Innovations, a small technology firm in Massachusetts. Last year I reviewed some of their CFR apps (some of which are free and some of which are paid), apps originally developed because Kasim Te at Tekk was an aviation consultant and helicopter instructor with a frequent need to review the applicable CFR regulations.
Upon starting LawStack for the first time you see the bodies of law loaded into the app. Subsequent launches bring you to whatever you were last viewing, which is helpful. Tap on a body of law to see the titles, then tap on a title to see the rules, then tap on a rule to read the text. One feature that I really like is that a date is located underneath each body of law so you know when the text was last updated. I wish all of the legal reference iPhone apps had this feature; nobody wants to rely on outdated law.
You can tap once on the text of the rule to make the header and footer disappear to maximize the screen real estate for the text of the rule itself.
You can search for rules by searching for words either in the body of the rule itself or in the header. Your search terms are highlighted in yellow in the text of the rule. You can also pull up your search history to run a prior search again, a nice feature.
You can use the iPhone's built-in copy feature to copy text, or you can e-mail the full text of a rule by tapping the button at the top right. The app also allows you to change the font size if you prefer larger or smaller type when reading rules; tap the info button at top right of many screens to do so.
In addition to the free bodies of law that are included, the app also contains a built-in store at which you can download additional free or paid bodies of law such as notable bills, most any title of the CFR or US Code (the developer is working to add them all), and state statutes from (as of now) California, Florida, Texas or Washington. Right now, many of these bodies of law are on sale. You can rearrange your list of bodies of law on the main page or delete any compilations that you no longer want to have.
I like the model of this app: you get a lot of great content for free, and as you grow to love the app you can choose to pay to add even more content. But even if you never pay for additional content, LawStack is a useful, free compilation of rules and laws that I encourage all lawyers using iPhones to check out.