Sorry, Dude, I missed your question earlier.
Nobody else has answered so I'll give it my best shot.
There is no direct way to insert an SD card into an iPad (1 or 2) BUT you can try one of 2 options. You can buy a gizmo, costing £25 from the Apple Store which doubles as an SD card reader and also has a slot to plug in your camera USB lead. This takes info from the SD card and puts it on your iPad. This works with iPad 1 and 2. It works with photo images and movie clips but as for other stuff like maybe Audio books or e-books, I just don't know.
The second option is to take a punt on a guy selling a very similar thing for under £5, including UK postage. on ebay (uk). I took the risk and got one and it works perfectly. Other folk told me that theirs was totally empty inside but that the seller sent a replacement straight away with no fuss.
Whether you want to risk that is down to you.
In fact, I'll try to upload various file types later tonight on an iPad 2 and let you know which work and which don't.
I should point out that I have absolutely no connection with the guy selling the cheapo doofahs.
Cheers,
Steve