Ok i see that, tq,
Is that means that my apps from the app store disappear to, or it can be redownload?
But is cydia for ios5 is available now? And if its availabe how can i download it to my ipad?
After you upgrade to iOS 5.0.1, you can either choose to restore the iPad to "like new" or "from a backup." If you restore it like new, you will have to manually transfer all your apps over to the iPad (either from iTunes or from the App Store). If you restore it from backup, iTunes will reload your most recent (pre iOS5.0.1) backup, which will put all your apps (and everything else) back on the iPad. In both cases, you won't lose the apps you've purchased from the App Store. Once you buy them, they're yours.
Cydia comes with the jail break. It is the jailbreaker's "app store." As you cannot, yet, jailbreak your iPad2 on iOS 5 (any version), it is not available to you and you cannot download, use or access it. You
cannot get Cydia without a jailbreak - and you won't have a jail break and not have Cydia.
Hope that clarifies.
Marilyn