On Saturday, 170 days after Apple (AAPL) began taking pre-orders for the iPad, supply officially caught up to demand, at least on Apple.com. Orders placed today now ship within 24 hours, like any other Apple product except the iPhone.

Getting iPad production up to speed has been a long slow process. Apple basically ran out of product the first weekend and didn’t catch up for months. The iPad 3G launch had to be pushed back, the international roll-out postponed by a month, and shipping delays at Apple’s online store reached as much as three weeks (15 business days).

By mid-May, shipping within 7-to-10 business days was the rule, a situation that persisted through June and July. It was only in mid-August that those delays began to shrink and finally disappear.

There’s no telling when the iPhone will catch up. There’s a 5-to-7 day wait for the iPhone 3GS, a three-week wait for the iPhone 4, and the white iPhone 4 still hasn’t shipped.

See also:

• Apple has run out of iPads
• iPad international launch postponed
• iPad demand outstrips supply, again
• iPad supply catching up to demand

[Follow Philip Elmer-DeWitt on Twitter @philiped]