Many existing iPad magazines use pure graphics for pages, so they're not compatible with VoiceOver, used by the blind. A new technology/geek culture magazine called The Magazine will address this. Free trials are available.
"Instead of the traditional labor-intensive magazine layout and expensive multimedia production, The Magazine’s article format is similar to Instapaper’s: one clean, adjustable, reader-friendly template with HTML, occasional images, and some small conveniences. It loads quickly, integrates well with sharing and system conventions (including text selection and VoiceOver), occupies minimal storage space, and shows the utmost respect for your time and attention."
"Instead of the traditional labor-intensive magazine layout and expensive multimedia production, The Magazine’s article format is similar to Instapaper’s: one clean, adjustable, reader-friendly template with HTML, occasional images, and some small conveniences. It loads quickly, integrates well with sharing and system conventions (including text selection and VoiceOver), occupies minimal storage space, and shows the utmost respect for your time and attention."