The translation was done by Anon2111 on AnimeSuki forums. Depending on the screen size, the text may be cropped (640x480 and 800x600 seems to works fine, but not 1024x768).
It's possible that the game freezes on the 2vs2 match if your opponents are Sakura and Kukuri. The game does not display the right dialog and the battle doesn't start.
I'm working on it, but I released this version for those who are interested ;]
The next patch will probably be in a single file that regroup Nanoha, Fate, Ruru and maybe an other character. but I have to correct the bug with this one...
I have to thanks Mic2070 for testing this patch and giving me some advices :]

A new english menu patch , for 1.04+ and lower, is available:

• Fixed : Low Qual. Video changed to Reduce graphics in Options Menu. I probably uploaded the wrong file for the previous patch :/
• Added : translation for Story mode difficulty in Options Menu.
• Added : Versus mode menu translation.
• Added : Pause menu translation.

Patch tool:

• You need the Framework .NET 3.5 in order to run it.
• Only a beta version, but working fine.
• Includes a BGM Manager.
• And about the "GDP Compactor" tab, it's for a future feature that allow you to compress all *.gdp files in /data folder. On my test I got a ~20MB GameData.gdp, and there was no problem to play with it instead of the 190MB one...

Version 1.04+ introduces a new configuration tool.
A translated version is available on the download section (translation is from Ayami).
Previous translation patch is not fully compatible with 1.04+ version (Story Mode Difficulty in Options Menu becomes invisible).

• Added translation for the network menu.
• Changed Low Qual. Video to Reduce graphics in options menu.

Translation is from here.
Again, thanks to coindetable for the link.

• Translation of main menu.
• Translation of options menu.
• Translation of keyconfig menu.

Credit to Anime Baka for the translation.
Thanks to coindetable for the link.