Hi, i have a problem with selecting device for testing. I heard that Corona supports ARMv7 processors only but can games from it run, for example, on ARM11?

Unfortunately ARM11 based processors only support ARMv6 so Corona apps will not run on an ARM11 based device. ARM processors that support ARMv7 are the Cortex A8 and A9 as well as Snapdragon (which is technically not an ARM processor but it supports ARM instructions such as ARMv7). Most devices that have been released in the last year or so support ARMv7 but make sure you check what processor they are running before you make a purchase.

Thanks

And do the older versions of Corona support other processors like those from Telechips?

Yes, the newest version of Corona that supports older devices (such as devices with ARM11 processors) is daily build 319 which can be downloaded here:
http://developer.anscamobile.com/sites/default/files/corona/2011.319/CoronaSDK-2011.319.dmg
The problem with older builds is that performance on Android is very slow in comparison to iOS so if you want to make a game you will have to make sure it is as optimized as it can be (and even then Android performance may still be poor). A good article to start with is Base2solutions Corona Tips page here:
http://www.base2solutions.com/walkabout/Corona%20Tips.html
You should also check out Jon Beebe's website here:
http://jonbeebe.net/
He has some awesome articles as well (in fact he is such a good Corona developer that Ansca actually hired him).