The new firmware is finally released and could be downloaded at Asus site for free. I will install it today or tomorrow, depends on the time that I will need to backup all my data.
Update:
Ok, I was able to reflash my Asus P525 with a new firmware and now I have windows mobile 6.0 on my device. It seems, that this OS is based on WM5.0, I don’t see big difference between WM5 and WM6, only a graphic design is now more similar to Windows Vista. There are some new utilities that the new OS offers. But I think, that I don’t really need such features how live search or live messenger on my PDA. I use mChat with ICQ protocol and it is enough for me. I noticed that WM6 needs a little bit more RAM than WM5. It is nor really good, but it could be worse. (Microsoft…)
My conclusion is that I did not lose anything with this update, but I don’t have many advantages with it too. A nice graphic, file crypting and some other (un?)useful tools, it is all new that I can find at this moment.