If the NIC isn't on the HCL, then chances are you're either SOL or have a LOT of hunting and fiddling ahead of you. Even then, there's not that great a chance of getting the NIC to work, at all... The HCL tells you when the drivers for the NIC are actually INCLUDED in the ESX/ESXi build. That's what you REALLY want... While you can add hardware to an ESX/ESXi version/build that comes out after the build is released, via the drivers available from VMware's site, there really are no 'generic' drivers that will work with ESX/ESXi. Put as simply as possible, ESX/ESXi is a proprietory OS so drivers for Windows, or versions of Linux, won't work. ESX has a Service Console that's installed as part of the installation that's based on a Linux distro, but even that is severely modified...
You're best bet would be to return that netgear card and pick up one that's on the HCL for the release of ESXi you're planning to use. I would make sure that the HCL has the NIC listed for more than just ESXi 4, make sure it's also listing ESXi 4.1 so that you're not looking to do this all over again when you go to 4.1...
Best cards, in my opinion, are those from Intel (and are on the HCL). Of course, you want Gb, and I would opt for a dual port NIC if not a quad port.
Moving forward, DO look at the official HCL for hardware BEFORE you purchase them. If it's not listed, I would NOT purchase it... Chances are, places like Staples won't have items you can use. You'll end up ordering them online, or going to a shop that can special order hardware for you (if they don't already have server class hardware in stock)... Single Gb NIC's should run you in the $30+ range with dual port NIC's running up to $150... I know it may seem like a lot, but these are true server grade NIC's, NOT just for any old desktop... Server class/grade hardware is held to a MUCH higher standard than what you'll slap into your average desktop (or even a high grade desktop)... The next closest set would be (true) workstation class hardware. I'm referring to those that are dual socket, server class processor powered with more than four memory slots (typically 8+).
BTW, a QUICK search under the VMware HCL IO Devices section using version ESX/ESXi 4.1, partner name: Intel, and Type: Network, yielded 85 hits... Some of those are for 10Gb NIC's, but there are plenty of 1Gb NIC's that will completely work with ESX/ESXi 4.1 as well as 4.0 releases (and many of them showing compatibility with even older reelases). Start hunting down the ones on that list on sites like newegg.com until you locate one you like (price and port counts)...
Personally, I'm using one dual, and one quad port Intel Gb NICs (both server grade) inside my ESXi 4.1 host at home... Yes, they were NOT cheap (~$400 for the quad, $150-$200 for the dual) but the stability and performance of them make the expense well worth it... Not to mention how long they are expected to last, even during extended high I/O sessions.
VMware VCP4
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