I used notepad++ on win and the command line tool bas2tap to create the tap. How I miss a debugger! :) Of course some quick test on the emulator (fuse) before coding.
For the title screen, Paint.net, imagetozxspec to convert to scr and command line tool tapmaker for the tap.
Then good old copy /b command to put pieces together!
Last thing I would like to do is put it on an audio cassette an play it on my speccy, for real authentic experience :D