苹果2011年度的WWDC大会发布了iOS 5，支持的硬件有iPhone 3GS、iPhone 4、iPod Touch 3代和4代、iPad和iPad2。iOS 5系统拥有200个新功能特性，其中iOS 5十大重要新功能特性最引人注目。下面提供苹果官方iOS 5下载地址，目前还需要ADC会员账号才能下载。国外网友释放出来的可以在网盘下载，如果不能直接可下载可以使用迅雷试试。
最新版本出来了：iOS 5 beta 2下载（网盘和官方地址都有）
iOS 5 Beta苹果官方下载地址：
iOS 5 Beta For Apple TV
http://adcdownload.apple.com/ios/ios_5_beta/apple_tv_software_beta.dmg
iOS 5 Beta For iPhone 3GS
http://adcdownload.apple.com/ios/ios_5_beta/ios_5_beta__iphone_3gs__9a5220p.dmg
iOS 5 Beta For iPhone 4
http://adcdownload.apple.com/ios/ios_5_beta/ios_5_beta__iphone_4__9a5220p.dmg
iOS 5 Beta For iPhone 4 CDMA
http://adcdownload.apple.com/ios/ios_5_beta/ios_5_beta__iphone_4_cdma__9a5220p.dmg
iOS 5 Beta For iPod Touch 3Gen
http://adcdownload.apple.com/ios/ios_5_beta/ios_5_beta__ipod_touch_3rd_generation__9a5220p.dmg
iOS 5 Beta For iPod Touch 4Gen
http://adcdownload.apple.com/ios/ios_5_beta/ios_5_beta__ipod_touch_4th_generation__9a5220p.dmg
iOS 5 Beta For iPad
http://adcdownload.apple.com/ios/ios_5_beta/ios_5_beta__ipad__9a5220p.dmg
iOS 5 Beta For iPad 2 WIFI
http://adcdownload.apple.com/ios/ios_5_beta/ios_5_beta__ipad_2__9a5220p.dmg
iOS 5 Beta For iPad 2 GSM
http://adcdownload.apple.com/ios/ios_5_beta/ios_5_beta__ipad_2_gsm__9a5220p.dmg
iOS 5 Beta For iPad 2 CDMA
http://adcdownload.apple.com/ios/ios_5_beta/ios_5_beta__ipad_2_cdma__9a5220p.dmg
国外网友释放出来的（网盘下载）：
iOS 5 beta 下载（推荐地址）：http://u.115.com/file/aq21clbo#
同步释放出来的还有iTunes 10.5
iTunes 10.5 (Mac OS X, 71.55MB)
iTunes 10.5 (Windows x86/32-bit, 72.48MB)