Comment 9 for bug 504771

For people using the adium theme who need a workaround can adjust /usr/share/adium/message-styles/ubuntu.AdiumMessageStyle/Contents/Resources/main.css like so:
@@ -114,7 +114,7 @@

 .tableBubble .message {
-
+ font-size:14px;
 }

 .tableBubble .message img {
@@ -139,7 +139,7 @@
        margin-left:7px;
        text-align:right;
        float:right;
- font-size:8px;
+ font-size:11px;
 }

@@ -149,7 +149,7 @@
        margin-left:0;
        position:relative;
        top:-2px;
- font-size:10px;
+ font-size:12px;
 }

 .myBubble .indicator {

Obviously, adjust to your taste, and you will have to completely close empathy and start it again to see the changes. Also, expect these changes to be lost on upgrade of adium-theme-ubuntu.