Apple’s soon-to-be-relaunched .Mac suite of online services has been experiencing severe problems today, with the main site unavailable, and iDisk functionality reported as slow to non-existent.

Apple’s .Mac is to be relaunched on 3G iPhone Day, July 11, as the cross-platform “MobileMe” service.

Apple CEO Steve Jobs announced MobileMe during his keynote at the Apple’s Worldwide Developer’s Conference, where he unveiled the new iPhone 3G and iPhone 2.0 - the forthcoming firmware update for iPhones that brings along a bunch of new mobile apps.

“MobileMe is a new service for your iPhone, iPod touch, Mac and PC, featuring Push email, Push contacts, Push calendar and more,” says Apple.

.Mac email addresses can be converted to .me addresses once .Mac users are upgraded to MobileMe.

There is no explanation from Apple for the suddenly poor service, and I expect it has something to do with the MobileMe launch.

.Mac users will automatically be upgraded to MobileMe on the 11 July launch of the service.

Let’s hope it works better than .Mac today…