With the new 0.7.4 update, you can join servers using their IP address. Here’s how-
1. On your single player worlds screen, tap the ‘Edit’ button
2. Once you’ve tapped that, you need to hit ‘External’
3. Enter the servers details. You can put the name as anything- it’s not that important, but you need the IP address and port. You can find the addresses of many servers @ http://mcpecake.org/servers
4. The server will now be saved to your worlds screen! Join it whenever it’s online, and enjoy the new update!