iBooks is now available on all iOS 4 Apple devices meaning that you can now catch up with your reading on your iPhone and iPod Touch.

The app not only gives you access to the all of the books in the iBookstore, it also acts as a PDF manager, letting you sync PDF files from iTunes as well as adding bookmarks and notes, highlighting certain text and check the meaning of words via a downloadable dictionary.

iBooks has been available on the iPad since launch but its only since the iOS 4 update have iPhone and iPod users been able to access the service. There are other eBook readers in the App Store though, like Kindle and Stanza.

Speaking of Kindle, Reuters is reporting that Amazon has slashed the price - maybe as a response to the growing threat from Apple's eBook assault. The Kindle is now just $189, a saving of $70 on its previous price.

Barnes & Noble is also feeling the Apple strain - it has cut the cost of its Nook by $60 to $199. Reuters has also stated that the share prices of both Amazon and Barnes & Noble are tumbling as well.

So, will Apple reign triumphant in the battle for eBook reader supremacy? And will you be happy reading books on a smaller screen with your iPhone? Let us know your thoughts on all of the eBook issues using the comments below.