Many persons are nostalgic about the C64 era with the Rob Hubbard tunes, etc ... but many (sometimes the same) persons are also nostalgic about the Atari ST era. That's why Arnaud Carre designed a file format to allow playback of tunes from Mad Max, Dave Whittaker, Tim Follin, and many other wonderful musicians from the 'ST scene' (Chris Huelsbeck, Rob Hubbard, Count Zero).
This format involves no M68000 emulation, only a Yamaha 2149 emulation, that's why it's possible to replay the YM tunes easily for many computers.
bITmASTER converted one year ago the first version of the 'port'. Now here is version 1.465 which should work on Risc OS 3.1+ computers (without the toolbox modules, as was necessary in the first version). It's not bug free, but it's pretty stable provided there's always half a meg (512 Kb) 'back in store'. Most notable missing feature is lack of Digital Drums (but I hope to see them real soon now !) and TAO's Sinus-SID. In case it crashes, it's better to have a copy of Dave Thomas's Dynamic Area remover patched by Justin Fletcher to work from RO 3.1 onwards.
You will need Acorn's OSLib to compile the sources for the front-end (80 Kb). Bundled with the front-end sources are the replay module sources (you will need an ASM assembler and the ARM_Reg.h file supplied with MPEGplay - I don't have any of these).
Here are some good links to look YM files from:
A simple core Wimp app to build your own convertor. All you've got to do is supply the conversion routine in BASIC and define some variables (name of app, filetype of conversion). Commented half in english/half in french, unfortunate english people ! Also supplied: 2 example apps based on WimpDIY (rejoin files, strips redundant spaces/carriage returns)
Installs a dagger on the iconbar that you can drag to other apps windons/icons to kill them. It kills without letting the app knowing so watch out !
An attempt to convert a superb program on the Atari ST called "Digital Filter" (How original!), whose purpose was to analyse and resample digital sounds. Unfortunately, I stopped in the middle of the conversion, due to important theoretical issues. Still unfinished. Give it a try, if you want to get ideas from it ...
A hacked version of the front-end by Kai Schlichting. Most notable modification: a double-click on a gzipped file will send ungzipped file to appropriate editor on iconbar. How cool !
Find in this ZIP archive the latest cjpeg, djpeg, rdjpgcom, wrjpgcom, jpegtran, already used in many RiscOS programs (ChangeFSI being one). Anyone fancy writing/updating a front-end for them ?
Click here for a 32-bit compatible version of the IJG jpeg utilities (offsite on Leo White's web site)
A little program that displays your font list with outline
fonts. Very handy for DTPers, and well worth the download ! New
version with bug fixes. 
This is a multi-document picture viewer decoding TGA, Jpeg, Gif and PPM. Highly recommended if you use POVray. Main programmer was Frank Lyonnet but this version patched by me (for example, you can ADJUST-close a picture to get the directory display it was read from).
I noticed some bugs occuring with several GIFs coming from the net, it must come from the GIF decoding routines that are slowly but surely aging (the animated GIFs did not existed at that time).
You may also download the current sources if you wish (300 Kb ZIP archive). It currently uses the RiscOS Lib, which is very painful to program. A lot of work would be needed to go Acorn's OSLib, but not so with the DeskLib (FYEO uses the attaching-events-to-windows feature, which would require quite some work with OSLib).
2003/03/03 Note: As I don't have the time nor inclination to develop FYEO2 myself, here's a link to Richard Murray's web site who intends to carry on with adding functionality to the program.
This is a reflexion game based on ancient african rules. My
version boasts (IMHO) superb raytraced graphics. I had sent it to
RiscUser 10 months ago for publishing (and earning money). Not a
single answer but it appeared in january'98 issue and I'm still
waiting to be paid (Well, actually I got 2 Risc User issues without
any explanation). So here it is for you, internet people, ready to
be downloaded ! 
NEW Should work with RO2 machines, unlike RiscUser version.
Yet another Shanghai game you will say ! Well, not exactly... This one allows several sets to be used alternatively and saves the best times, along with the names of the hiscorers. This version is a patched version from Julian Jiggins, whom I greet, wherever he is !
New version with beautiful tiles taken from KDE/Linux
Gobang is a conversion of a game I used to play on the atari ST. It's like Connect4, but without gravity. Quite interesting.
A modified version of Mike Williams' game that doesn't use the sprite area anymore, thus allowing compatibility with David Pilling's SparkFS. The aim of the game is to discover as much of the map as possible with your ship, without touching any background object. Difficulty can be compared to PlanetLand, which I also enjoyed very much.
A modified version of R.R Chasmers' game that doesn't use the sprite area anymore, thus allowing compatibility with David Pilling's SparkFS. This is a 2-player reflexion game where each player alternatively picks up a tile numbered from -9 to 9 along a row or column, the number being added to one's current score. Highest score wins.