Ask HN: Need advice on building a network card. Where to begin?

I'm trying to build a network card, or rather add on some special functionality onto a programmable network card. I am a developer and have no experience with hardware. I was hoping to find someone on HN to bounce a few questions off of.

1) Where should I start my hunt for a programmable usb network card?

2) Could I email you to ask a few questions about creating specialized network cards?