1. A windows shortcut is to use Alt+#### on the numeric keypad to enter characters. That works even if the Alt-X is not available in a prog. E.g. Alt+0255 will insert the ÿ for you. You do need 4 numbers
2.
http://www.phraseexpress.com/ has a 'autotext inserter' free for personal use that I found about here on MR
Define the text to type and the replacement text is inserted in the document. E.g. I defined y:: as ÿ so now when ever I type y:: I automatically get the ÿ.