Docs to Go Basic is included in OS 4.5, which you have according to your user info. You can upgrade to the Premium edition described above to get a PDF viewer. This is one option; there may be others. Some, maybe all, have free trials, but I'm not aware of any that are free.
RepligoReader and BeamReader. The one that now comes with DocsToGo is lacking features in comparison to the other two. BeamReader is free during Beta testing. It seems to be the best so far, because it's the only that view pdf files containing music font correctly.
Posted from my CrackBerry at wapforums.crackberry.com
As cdf3 said, BeamReader is free during the beta period. However, their own web site indicates that they don't know what the pricing will be after the app is released. Upgrading to the premium version of Documents to Go will run you $50 per year, or $70 for no time contraint. Repligo Reader costs $24 (20% off) until Nov. 12, after which it will be $30.
There has been speculation that PDF to Go (included in Documents to Go Premium) is a stripped down version of Repligo Reader due to the copyright notice in PDF to Go.
I just went to the site and added Repligo Reader to my cart and then added the promo code PRO35 and with worked fine. Of course, I didn't actually check out, but the cart shows the 35% discount.
