WP 2.6 charset problem

Hello,

I have problem maybe like you. I have upgraded from 2.5.1 to 2.6 and some of my posts have been changed. Some charts aren’t shown correct. I have also looked around here and checked some tips but still doesn’t work. For example, the “μ” is shown like “?” mark. Even when I try to edit the posts it still shows the incorrect marks. Any ideas?