There are different options for it.
Some of them are the following:
1.Download free themes directly to your phone using WAP or into your PC and transfer it to your phone via motorola L7 Datacable or via Bluetooth
Click the link below for Free motorola L7 themes:http://www.mobileheart.com/cell-phone-reviews/motorola-12/motorola-SLVR-L7-817.aspx
save to your PC and transfer to your phone. U can also type the same link to your WAP browser and download themes straight to your phone.
2.Buy themes that are compatible to your phone through WAP or the internet using this link:
3.U can also download/buy themes from your network provider for a price (only if your network supports it).
That's it, u can download themes now for your motorolaL7 phone.Note: Please rate this solution if it works for you, specially if it has solved/answer your question(s).
It will be much appreciated, thank you!
For further questions on how to transfer downloaded themes from PC to your phone, don't hesitate to ask me. I'm always open for questions...Good Luck and Enjoy Downloading!