When we reported Tuesday that Google Drive is here, and you can install it "right now," some of our readers were understandably frustrated that they couldn't, in fact, install it right away.

Some people who signed up were greeted with messages saying that their Google Drive wasn't "ready" yet, with the option to get an e-mail notification when Google had room to let them in. What we're hearing from readers on Twitter is that people who don't get into Drive immediately are rewarded for their patience within a few hours or a day. A handful report having had to wait a couple of days, but 24 hours seems to be the longest wait for the vast majority of folks.

I got in right away, after signing up within five minutes of the service being announced. I have two Google accounts, though, and to test out its availability, I tried to sign up with my second account late yesterday afternoon. Within about 20 hours, I was in. My colleagues are reporting getting in right away, or enduring waits of between 12 hours and a day. Google declined to tell us how many people have signed up and how many have gotten in. The service is rolling out "over the next several weeks," the company told us.

Users of the Google Apps service we've heard from are reporting quick, if not instant, turnarounds—although Google said Apps users still have to go through the same opt-in process as any other user, so it may just be luck.

In a Google Apps administration support page, Google says it is transitioning users' Google Documents list to Google Drive by early summer. The current "opt-in period" will be followed by a temporary opt-out period, and then a full transition of all Apps users to Drive for document storage. Drive appeared in the Google Apps control panel for all administrators on Tuesday, and users at organizations that are Apps customers will get access at the same rate as Google's non-business users. There's one exception to that—users who work for organizations that have chosen the slower, "scheduled release" track for Google Apps won't be able to opt in to Drive until the next batch of scheduled updates.