Most PCs should read Atari Floppies unless you used some extended format, (not sure on the 720KB ones though).
Also, if the Floppies were formatted on the Atari, you most likely just need to Write the Boot Sector, (from a similar size Track & Sector Disk), to the Atari Floppy... even Macs read them.
If you still have the ST, or know someone with an Atari, you'they could tranfer them by Null Modem Cable, or even by Modem, and/or the Internet.