You can try [Link: remotecentral.com]
though it's a tad obsolete, most of the information is valid.
Some codes will need to be learned, especially for newer types of devices and brands, but many old standards will still work from the database. With that said, I always prefer to learn anyways. Guarantees I get exactly what I want. Thankfully Pronto hex code became the standard, so discrete codes are usually posted in it.
Bitmap software is whatever works for you. I did my buttons manually in Corel, some folks use button tools, or you can just copy other layouts without reinventing. Study how other files you like are built up. BTW, you want 24-bit PNG files with transparency.
Also be sure to search the forums for help! Every piece of information ever asked or learned about the Pronto is in this database, waiting to help!