The magazine comes as four PDF files, which are readable on RISC OS using the !PDF application. The files range from 1.4MB to 3.1MB so shouldn't strain your connection too much to download, and they provide some nice evening reading.
According to an article on another website, Acorn User plan to do this every month, uploading the month prior to the currently on sale edition to their website for all to see.
If the news from a couple of months ago isn't enough, why not go even further back and read Acorn User issue one or Acorn User issue two on this very promising website. Acornmags.co.uk also houses some historical issues of A&B Computing, Electron User and Elbug. And of course, drobe have their collection of Acorn User magazines available to look at on their website.