Apple issued an apology for difficulties with its MobileMe service and offered subscribers a free 30-day extension.

The company's replacement for the .Mac service was rolled out late last week, but users reported multiple issues with backing up data and accessing the new Web portal me.com.

"We have recently completed the transition from .Mac to MobileMe. Unfortunately, it was a lot rockier than we had hoped," the company said in an e-mail to subscribers. "Although core services such as Mail, iDisk, Sync, Back to My Mac, and Gallery went relatively smoothly, the new MobileMe Web applications had lots of problems initially."

Some users have been upset that the service doesn't offer true push capabilities, as changes made from Macs and PCs sync once every 15 minutes, not in real time.

The company acknowledged this in the e-mail and said it would drop the word "push" from MobileMe's description until "it is near-instant on PCs and Macs too." Apple did say that changes made from the iPhone and Web apps are immediately synced to and from the MobileMe "cloud."

Apple is giving MobileMe subscribers an automatic 30-day free extension to the service to make up for these issues, the company said.

The company said the service is functional now, but many customers on Apple's MobileMe support forum are still reporting problems.

MobileMe is a subscription-based wireless data syncing service that's often been described as "Exchange for the rest of us."

It works with the iPhone's calendar, contacts, and mail applications in addition to working with Mail, iCal, and Address Book on the Macintosh and Outlook on Windows. Users can manage their accounts through Me.com from any Web-connected device.

Customers can also use the service to store and share photos, videos, and other data wirelessly. The service costs $99 per year and offers 20 GB of storage, with additional storage costing extra.