Apple released iOS 4.1 on Wednesday for the iPhone and iPod touch. The update includes several new features such as Game Center, HDR photo capture, HD video upload support and TV show rental support.

iOS 4.1 also fixes several security issues including a flaw that could let an attacker redirect FaceTime calls with a maliciously crafted certificate, and a flaw where maliciously crafted TIFF or GIF images could be used to crash apps or run arbitrary code. WebKit for iOS received its fair share of security patches related to maliciously crafted SVG files, the handling of text nodes and element focus, fonts, HTTP redirect handling, CSS encounters, JavaScript arrays, and more.

The update is compatible with the iPhone 3G, iPhone 3GS and iPhone 4, as well as every iPod touch after the first generation model. Not all iOS 4.1 features, however, are compatible with every device.

iTunes iOS 4.1 update dialog

To download and install the update, launch iTunes on your Mac or Windows PC and connect your iPhone or iPod touch. If an update dialog doesn’t appear, select your iPhone or iPod from the Library list, select the Summary tab, and click Check for Update.

Some users are reporting on-again-off-again availability of the update, so you may have to try more than once to get the update to show up in iTunes.

To learn more about what iOS 4.1 includes, check out our iOS 4.1: What You Need to Know article, and our iOS 4.1 upgrade guide shows you what to do before and after installing the update.

iOS 4.1 is a free update for iPhone and iPod touch users, and weighs in at 589 MB. iOS 4.2 will be available in November and will include iPad support.