The Netathlon software provides a Virtual Reality rowing course on which you can row against other people over the internet or over a network. Alternatively you can record a session and train against it at a later date. There are various different courses, the virtual reality graphics are cutting edge.
View WebRacing.org NetAthlon Info
Currently Netathlon is Windows compatible only.
View "How it Works" PDF
Pentium 4-class CPU, 512MB RAM, DirectX 9c-compatible graphics with 256MB graphics memory, Windows XP
Pentium dual-core processor, 1GB RAM, Nvidia or ATI graphics with 512MB graphics memory, Windows 7
Note: NetAthlon 2XF is compatible with, Windows XP, Vista, and 7, all 32 and 64-bit versions.