After creating some programs you may want to put them in Mirage OS. This is possible by putting a colon on the top line on your program. Well, here's the deal: DON'T!. Doing this on a calculator with an OS greater than 1.12 (which is any new Ti-83+ and all Silver Editions) will cause the calculator to crash when they try to run your program. There's a 1/10 chance that the person you give your program to will have OS 1.12 still on their calculator. This means that for every 10 people you distribute your program to, 5 of them will be after your neck, 4 of them won't care, and 1 will think your program's just great. So the deal with putting your programs in Mirage OS is: Don't. Mirage OS 2.0 will hopefully have this bug fixed when it comes out.
You may also notice that programs such as Omnicalc and Symbolic add extra tokens to be used with BASIC programs. Once a BASIC program has these tokens in it, it cannot be transferred to another calculator. If you're writing a program just for yourself, then you can use these, but if you're writing it for distribution, then do not use these tokens.