Enable view of longer message subject lines for your messages on your Blackberry.

1. In a message list, press the Menu key.

2. Click Options.

3. Click General Options.

4. Perform any of the following actions:

• Set the Display Message Header On field to 2 lines.
• Set the Display Time and Display Name fields to No.

5. Press the Menu key.

6. Click Save.

Source: Blackberry Users Guides