AttachAnyway is a PoC OllyDbg plugin designed to show how to remove a process' hook on NtContinue by the anti-debugger-attach method devised by Piotr Bania here:
http://pb.specialised.info/all/anti-dattach.asm
This is not intended to be a universal plugin for all anti-attach methods, just one example of how you can do it. It works by enumerating all processes, searching their virtual memory space for a JMP hook on the NtContinue method, then replacing the jump with the original bytes from a non-hooked process, then calling the OllyDbg Attachtoactiveprocess API.
attach-test.exe is an assembled version of Piotr's anti-dattach.asm you can use to test the plugin with.