BoxWave has Cleartouch anti-glare for the iPad. While I generally use the clear ones and not the anti-glare for my other gadgets, for the iPad I would highly recommend getting an Anti-Glare. I have one on my iPad for 2 main reasons:
1) The iPads glossy screen is beautiful but can be difficult to read in certain environments such as in the sun. The anti-glares matte finish helps to defuse the light so its not reflected strait into your eyes.
2) The glossy finish on the screen is a fingerprint magnet. But with an anti-glare, you wont run into that problem fingerprint.
As for what company you should go for, I would recommend BoxWaves ClearTouch. In my experience, you DO get what you pay for. Ive used several different brands, many of them are cheap and low quality. Ive learned my lesson. I decided to go with a well recognized brand for my iPad. The quality and clarity of their screen protectors is amazing and unmatched! Since the iPads screen is glossy I went with the anti-glare version. It significantly cuts down on the glare and another bonus is that it reduces fingerprints from the screen from all that tapping and touching!
http://www.boxwave.com/products/cleartouch/cleartouch-screen-protector-apple-ipad_3779.htm
Installation was easy. Just make sure you have scotch tape in case you get dust or lint stuck under the side that adheres to the screen. The sticky side of the tape is a great way to remove any specks of lint or dust that may get trapped, causing air bubbles. In case you accidentally get A LOT of dust trapped underneath, the ClearTouch is nice because you can wash it off with a little soap and water.
Some people say Invisible Shield is good, but I noticed that their screen protectors have an orange skin (aka orange peel) like texture to it which makes the screen look somewhat distorted. It also feels rubbery to the touch, which makes it difficult to swipe around the screen. While Id recommend them for maybe a phone, I dont for the iPad. For me personally I always seem to go back to BoxWave.