Evernote offers apps for most PC, Mac, and smartphone OSs, and is versatile enough for law enforcement or any other use. When you see something you want to remember or keep track of, send it to Evernote. This applies to photos, text notes, e-mail, Web pages, articles, and just about anything else. Evernote stores a copy on your device and on the Evernote server, where you can retrieve it at your leisure. You create tags and categories to fit your own needs. A free Evernote account allows you 40 MB of uploads per month, which is plenty enough for most people. If you get to be an Evernote junkie, you can get a premium account for $5 per month and upload 500 MB.
Another type of information manager is eWallet, which offers versions for most smartphone platforms, PCs, and Macs. eWallet is for the kind of information you might carry in your wallet: account numbers and passwords, serial numbers, prescriptions, clothing sizes, PINs, etc. It comes with template "cards" for most any kind of information you're likely to need, and there are blank general purpose cards and design-your-own versions.
The database is encrypted on whatever device you have, so if it does fall into the wrong hands, it will be useless without the password. When you make a change on one platform, you can synchronize it to the other, so your mobile and desktop files stay concurrent. Among the files in my eWallet are cards for each one of my guns, with make, model, serial number, and place of purchase. I have similar files for my computers and other electronic gear. If something goes missing, I always have its details.
You can use your smartphone to replace some of the reference books and "cheat sheets" you've collected (or you will create). Droid Law is a free database for Android phones, and is necessary to run any of the various state and federal code references they have for sale. Why carry a book around when you can have the entire criminal and/or vehicle code for your state on your phone? There are similar applications for other smartphone platforms, although you may not find a ready-made solution for your jurisdiction.
If not, consider making your own. Every smartphone platform has one or more flat-file database applications available. It wouldn't take all that many evenings to create your own criminal code database, and populate it by cutting and pasting from the online version of your state's statutes. You might even be able to sell your work to other officers (but check copyright issues before you try).