Apple has made a very minor hardware change to the iPad in the days running up to it going on sale to the public. What was previously described as the “mute switch” in Apple’s diagrams is now referred to as “screen rotation lock”.

It goes without saying that the iPad is much like the iPhone in the sense that it can change screen orientation just by changing the orientation of the device due to the use of an internal accelerometer. This hardware switch would negate this and lock the screen the orientation it was currently in when the button is pressed. This should come in handy for users who are lying down.

In other hardware news Engadget points out that Apple has submitted two filings to the U.S. Federal Communications Commission, and these filings have now shown up in the FCC’s online database.

Apple, of course, has a track record of timing its FCC filings perfectly so that virtually nothing is revealed before Cupertino wants it to be, and frankly, you’re not going to get much here that you didn’t already know — the photographs (both external and internal) and the user manual are both still under confidentiality. Both units were tested for WiFi 802.11a/b/g/n and Bluetooth, while one — model number A1337 — adds in GSM 850 / 1900 and UMTS 850 / 1900, so it appears that Apple has bundled all of its 3G and non-3G models into just two filings regardless of storage capacity.

These filings come with requests for 180 days of confidentiality on things like external and internal photos and user manuals.

Images courtesy of MacRumors.

Apple has posted information regarding their iPad Battery Replacement Service, which offers replacement of the entire device instead of just the battery for $99 (plus $6.95).

You will receive a replacement iPad that will not contain any of your personal data. Before you submit your iPad for service, it is important to sync your iPad with iTunes to back up your contacts, calendars, email account settings, bookmarks, apps, etc. Apple is not responsible for the loss of information when servicing your iPad.

Apple estimates that it will take around a week for the transaction to complete and can be set up through Apple’s retail stores, Apple technical support, or Apple Authorized Service Providers. Of course, any iPad that has had unauthorized service of modifications performed on them will not be covered under the program.

Let me be clear, I don’t know how Apple functions, but to me this battery replacement program says one of two things. Either Apple thinks they won’t be replacing too many of these batteries, or (more likely) Apple is selling these devices at such a markup that they can afford to replace the entire device if something should go awry. Regardless, replacing the entire device simply because the battery went bad seems a little odd.

Apple is now allowing customers to pre-order any of the six iPad models starting today. The three Wi-Fi models will arrive on on April 3rd, the 3G models will arrive in late April. Fortune predicts that as many as 50,000 iPads were pre-ordered in the first two hours of being able to do so.

Apple has also shed more light on the 3G cellular service for the device and how it works. As reported at the launch of the iPad in January, customers can purchase 250MB of data for $14.99 a month, and unlimited data for $29.99 a month. Before now however, it wasn’t clear how this would be handled. With Apple’s new information, it shows that consumers can activate and deactivate their service (in monthly blocks) from the iPad at anytime.

You can check your data usage in Settings on your iPad anytime. And iPad will even let you know when you’re running out. You’ll get three alerts as you near your 250MB limit — at 20 percent, 10 percent, and zero. With each alert, you can choose to add more data or wait and do it later. Tap Now and iPad opens the Cellular Data Plan window so you can update your data plan.

Here is an image of one of the panels where you can manage your data.

Within this preferences panel you can change plans or cancel at any time. That means a users reaching their 250MB limit could switch to the unlimited plan on the fly. Lastly, users will be prompted with 20%, 10%, and 0% warnings when reaching their 250MB limit.

For what it’s worth, I ordered the low-end 16GB Wi-Fi only model. Did you pre-order an iPad, what do you think? Leave a comment!