Limit plugin to blog admin only -> check priviledges

I've been playing around with some plugins and have created my custom ones based on those. Though, I ran to a major bug while beta testing those plugins:

It seems like when blog address is and plugin editor settings page is

blog owner of can also access and change settings.

I'd appreciate if you could help me with this and tell how to check if user have priviledges to modify setting of other blog.

I know it's quite easy thing to do (lol, for someone who CAN DO IT), but I just can't figure it out... I just don't wan't to create SQL statements when I know it's already build in MU.

btw, these plugins are in plugins, not mu-plugins folder if it makes any difference.