If Michael Robertson is right — and I believe he is — Apple (AAPL) is about to use its $85 million purchase of Lala to create a browser-based music service that will let users access their iTunes music collections from the Web.

The service could become available as early as next Wednesday, says Robertson, a 12-year digital music industry veteran, as part of Apple’s “latest creation” extravaganza.

But you don’t have to wait until next week to see how it works. You can download Lala’s free Music Mover from Lala.com and start uploading your library today. You just have to be prepared to give it some time to get the job done.

I started uploading my library three days after Apple’s Lala deal was announced. A week later, the Music Mover was still hard at work in the background, uploading and transcoding a 6,000-song library that by today’s standards is rather modest. Here are the facts:

• My iTunes library: 6,198 songs
• Upload time: 1.75 minutes per song (over cable modem)
• Number of errors: 286
• Songs uploaded: 5,698
• Total time spent: 7.5 days

It’s nice to know that my music is now available to me from anywhere on the Web, although I’ve only listened to a couple songs so far to make sure it worked.

And it’s not clear yet whether I will have to go through the process again when, if Robertson is correct, it becomes a feature of Apple’s next version of iTunes. I guess we’ll find out next week.

You can read Robertson’s Apple’s Secret Cloud Strategy And Why Lala Is Critical on TechCrunch, where it was posted Tuesday.

[Follow Philip Elmer-DeWitt on Twitter @philiped]