Best for: if you just want to play files online on your computer / tablet / phone etc. However you can't download the files to play offline or to write them to a CD. A useful feature allows you to play a tricky section in an endless loop.
Click here for Nelson Mass on Cyberbass
Best for: somewhere between Cyberbass and John Fletcher - you can play files online or download them. Free to try, but a donation is requested if you find them useful. Uses a synthesised human voice.
Click here for Nelson Mass on Choralia
(Jenkins Requiem not available on Choralia)
John Fletcher Music
Best for: downloading files so you can play them offline, load them onto a phone/mp3 player, or write them to a CD. (You can also play them online but it's fiddly to navigate to the files each time.)
Click here for Nelson Mass on John Fletcher
(Requires you to register and login - the choir does not have an account. For out of copyright works such as it is free to register. For in-copyright works, a four month individual membership costs £4 for 4 months, or £10 for a year.)
Best for: ready-made CDs of your part (notes not voice). The most 'professional' of the sites mentioned here; CDs typically cost around £10. The files are also available online, but you still have to pay.
Click here for Nelson Mass on Choraline