for those of you who are waiting for blackberry 5.0 os for curve 8520, wait no more. do download the os here :
Blackberry 5.0 OS for Curve 8520
________________________________________
Software For BlackBerry® Curve(TM) 8520 Smartphone
BlackBerry Handheld Software v5.0.0.860 (Multilanguage)
Package Version: 5.0.0.860
Consisting of:
* Applications: 5.0.0.509
* Software Platform: 5.2.0.47
* File name: 8520wifiM_PBr5.0.0_rel860_PL5.2.0.47_A5.0.0.509_Wind_Hellas.exe
* File size: 117.78MB
Note: The Software Platform and Applications version numbers can be found under Options-About screen on the handheld
p/s : You need to register first before downloading.