Guilderland, N.Y. ? A new way to borrow audiobooks from the library involves no CDs, no car trips, no fines and no risk of being shushed.

Rather, public libraries from New York City to Alameda, Calif., are letting patrons download Tom Clancy techno-thrillers, Arabic tutorials and other titles to which they can listen on their computers or portable music players – all without leaving home.

Librarians say such offerings help libraries stay relevant in the digital age.

Barbara Nichols Randall, director of the Guilderland Public Library in suburban Albany, said the library considered the needs of younger readers and those too busy to visit.

“This is a way for us to have library access 24/7,” she said.

There’s still one big hitch, though: The leading library services offer Windows-friendly audiobook files that can’t be played on Apple Computer Inc.’s massively popular iPod player.

Vendors such as OverDrive Inc. and OCLC Online Computer Library Center Inc.’s NetLibrary have licensing deals with publishers and provide digital books using Microsoft Corp.’s Windows Media Audio format, which includes copyright protections designed to help audiobooks stand apart from the often lawless world of song swapping.

Visitors to the audiobook section of the Guilderland Public Library in Guilderland, N.Y., look at their choices of books on tape on Aug. 18. The library is now offering a method where their users can download books to their home computer or any device that will play Windows-friendly audiobook files. Owners of Apple iPods, however, cannot use the service because of compatibility issues.

A patron with a valid library card visits a library Web site to borrow a title for, say, three weeks. When the audiobook is due, the patron must renew it or find it automatically “returned” in a virtual sense: The file still sits on the patron’s computer, but encryption makes it unplayable beyond the borrowing period.

“The patron doesn’t have to do anything after the lending period,” said Steve Potash, chief executive of OverDrive. “The file expires. It checks itself back into the collection. There’s no parts to lose. It’s never damaged. It can never be late.”

Potash said about 1,000 libraries have signed up for OverDrive’s audiobook service since its debut late last year. NetLibrary, teaming up with Recorded Books, launched a similar service in January and counts 200 library customers.

Libraries offering audiobook downloads range from large institutions in New York and Los Angeles to smaller ones for Cleveland, Ohio, Maricopa County, Ariz., North Little Rock, Ark. and Omaha, Neb. The Hawaii State Public Library System signed up earlier this month.

Guilderland pays NetLibrary about $6,000 a year for more than 850 titles. Randall considers that a good deal, noting that a single audiobook can cost the library up to $80 when bought on CD.

Under the NetLibrary program, Guilderland gets a set number of downloads for all titles each year, and a single title can be borrowed by multiple patrons simultaneously as long as the cap hasn’t been reached. Downloads over the cap cost extra. Patrons must provide their own audio players, although they may listen on their home computers if they do not have one.

Other libraries make different arrangements. OverDrive, for example, generally takes a more traditional approach. When a copy is checked out, no other patron may download it until the borrowing period ends.

It’s still unclear what impact such services will have on audiobook download sales from companies such as Audible Inc., although one analyst suggested it could inspire more sales as patrons buy for keeps a title they had borrowed.

“It’s certainly smart for the publishers to do this,” said Phil Leigh, a senior analyst with Inside Digital Media.

Users of iPods can still listen to books purchased through sources such as audible.com or Apple’s own iTunes Music Store, but the library services, for now, are geared toward computers and devices that support Windows Media Audio files. OverDrive files can be burned to CDs and converted to iPod friendly formats, but NetLibrary’s cannot.

Apple spokeswoman Natalie Kerris said the company has no plans to change its copy-protection formats and would not comment on the incompatibility issue.

Librarians say they have heard complaints from iPod users, but there’s little they can do beyond waiting for the industry to sort out its differences.