I'm very new to Seam but I've been there a couple of times :)
There are a couple things to check
1. Make sure UTF-8 works with database. Using MySQL, I remember pulling my hair out many times at table and even column level wrong encoding. This is esspecially important if you change encoding after you create your database.
2. Don't know which server you're using but with apache make sure you set UTF-8 with the listener. This is the setting that affects your form posted field encodings
3. Again not with Seam but using facelets with Tomcat, I recall a setting a context param in web.xml
<context-param> <param-name>javax.faces.DEFAULT_SUFFIX</param-name> <param-value>.xhtml</param-value> </context-param>
Hope these help,
Oops. wrong paste.. meant to write...
<context-param> <param-name>com.sun.faces.disableUnicodeEscaping</param-name> <param-value>true</param-value> </context-param>