Einstein development has picked up on GitHub at https://github.com/pguyot/Einstein. Paul Guyot returned to make some fixes and migrate it from Google Code to GitHub, Steven Frank has made some updates for building on new versions of OS X (and iOS? I can't recall), and Matthias Melcher has been continuing to make excellent progress on replacing ROM code with native code for improved performance.
I know an ethernet card emulation had been added at some point and that it worked for HTTP access, but I can't recall which platforms other than OS X were supported or how reliable it was. Since it connects through the host device's network/Internet connection, that can work with WiFi.
Naturally, the big issue with Internet connectivity at this point is the lack of SSL support. Beside some of the research I had done in planning my own port of PolarSSL to NewtonOS (see NewtSSL on Google Code, which I sadly haven't had time to continue yet), Jake Bordens has experimented with compiling CyaSSL.
I know an ethernet card emulation had been added at some point and that it worked for HTTP access, but I can't recall which platforms other than OS X were supported or how reliable it was. Since it connects through the host device's network/Internet connection, that can work with WiFi.
Naturally, the big issue with Internet connectivity at this point is the lack of SSL support. Beside some of the research I had done in planning my own port of PolarSSL to NewtonOS (see NewtSSL on Google Code, which I sadly haven't had time to continue yet), Jake Bordens has experimented with compiling CyaSSL.