Following GaMedic's Step by step tutorial, I was able to successfully flash my ppc6800. Despite much fear and anxiety of screwing up. All went well and I think I'm being to understand all this phone hacking stuff.
I had an incident though when I wanted to do a re-flash to do a few tweaks I couldn't activesync. Panicking, I tried flashing from my SD card. I got a grey screen which said something like "No image file" (I don't know, it was too quick) and I was facing the bootloader. Panicking even more, I retraced my steps, trying to see where I went wrong.
Long story short, it turned out that I needed to disable advanced networking (start/settings/connections/usb to pc). I did so and my phone connected just fine. I still never got to the bottom of the SD card situation though. However, I'm happy. My phone still works and now I can show off my budding geekiness.
A huge thanks to GaMedic and other authors of splendid tutes.
Cheers!