*This will not change the base your calculator operates in. It allows you to convert base ten to other bases.*
Omnicalc, from [Detached Solutions] has the ability to change bases on your calculator. Put Omnicalc on your calculator, then go to APPS > Omnicalc > [ENTER] > 1: Install/Uninstall. It should say that Omnicalc has been installed. Then, from the main menu, press 2: General Settings > Toggle "Base Conversion". The box should be filled in (all black).
Go back to the main screen. Hold down the ON key and then press LOG. You can then enter a base from 2 to 36. Type in a number in base ten, and it will give it to you in whatever base you put in.
Different bases will have different notations. Binary numbers will be followed by a "b", octal by an "o", and hexadecimal by an "h".