Apple opened up preorders for the iPhone 4S first thing this morning. At 12:00am Pacific time (3am Eastern) Apple.com was supposed to make the switchover from explaining when preorders would be available to actually making them available. That eventually happened, but not right on schedule — for at least a few minutes the site was returning an error to visitors.The initial error on store.apple.com was a standard one — Http/1.1 Service Unavailable — and it lasted for at least 15 minutes after 12:00 PT (much to my dismay).Cnet reports a rash of different errors on the site, including the generic “An error occurred”. Eventually a reservation system was put in place so that spots could be held without buyers going through the entire process.By 6AM this morning (when I placed my order) everything was working normally. My ordering process was fast and efficient with no errors. At the end of the process I paid and was told I would have my iPhone 4S on October 14th, the first possible day. After about 15 minutes a confirmation email arrived.Despite all indications of a considerable number of sales — including the problems with Apple’s site this morning — the iPhone 4S is still said to be arriving at customers’ homes and businesses on October 14th. This won’t necessarily be the case for long, at least if the past is any indicator. Apple fans will remember that the ship date for a preordered iPhone 4 was pushed back a number of times, eventually to 3 weeks after the official release date.This hasn’t happened yet with the iPhone 4S, possibly because Apple expected the demand and manufactured a greater number of handsets. Building the handsets surely would have been easier this time as the iPhone 4’s structural components are the ones Apple has had made tens of millions of times over the last 16+ months. Availability of the components, like the A5 chip, could potentially have been the bigger issue, but it hasn’t come up yet.And, of course, there is also the possibility that preorder demand for the iPhone 4S is lower than Apple expected so the limit on the initial batch of preorders has not yet been hit. Last year Apple took 600,000 orders for the iPhone 4 on its first day of availability. We’ll soon see if the iPhone 4S matches that number.