Some time ago I've started working on a tool that would allow me to quickly upload files over ethernet (netusbee) to my Atari. This was mainly meant to speed up my development iteration but in the end I've decided to add web interface for the benefit of general public. It doesn't require Sting or MiNT. It's a self-contained binary with uIP embedded TCP/IP stack with DHCP. Run it on your Atari and point your PC browser to the IP address you'll see on the Atari screen. As far as I can tell it works on all TOS machines (tested on ST, TT, Falcon and CT60).

It supports drag&drop of files from your PCs desktop.
It's largely unfinished. I'm hoping someone will help me get HTML part to the point it will be a genuinely useful tool.
Code and a binary can be found here:
git repo: https://bitbucket.org/sqward/uip-tools
binary: https://bitbucket.org/sqward/uip-tools/downloads/
Hope someone will find it useful.
uIPtool tutorial