In fact, you can change any messenger font
, using the skinning system, as djdannyp said.
Just add this
xml code:
<Resources>
<Replace>
<Strings>
<String Id="3018">font name</String>
<String Id="20951">font name</String>
<String Id="20952">font name</String>
<String Id="20953">font name</String>
<String Id="20954">font name</String>
</Strings>
</Replace>
</Resources>
to a <ResGroup>
and add
xml code:
<Fonts>
<Font><File>font file</File></Font>
</Fonts>
below the <SkinInfo> in your SkinInfo.xml file.