https://github.com/moneromooo-monero/monero-wallet-generator is a browser based offline wallet generator for Monero. This means you can generate a new Monero address/wallet without the simplewallet binary. The page is self contained, so is suitable for saving and using offline (ie, possibly on a computer which is not connected to the network).
The git commits are GPG signed. If you know how to do so, I encourage you to verify the signature is a valid one. My key can be found in the Monero source tree:
https://github.com/monero-project/bitmonero/blob/master/utils/gpg_keys/moneromooo.asc
The Cryptonote code was adapted from MyMonero. I had to change the way it derives the view key to make it compatible with simplewallet. This means the wallets generated are NOT compatible with MyMonero, but with simplewallet.
Wallets generated with monero-wallet-generator can be restored at any time with simplewallet:
./build/release/bin/simplewallet --restore-deterministic-wallet --wallet-file mynewwalletfilename
Choose a new password, copy the seed you got from monero-wallet-generator, and the wallet will be restored.
Only English seeds are supported, due to issues with UTF-8 preventing restoring other languages. This will hopefully change in the future (though low priority).
Same thing for non Firefox browsers. I don't have them, so any fixing there is low priority.
Last, no warranty. If you have the opportunity, a test restore before moving monero to a new wallet is a good idea, though I guess it kinda defeats the purpose.
YES!! you are awesome Moneromooo! Is it okay if I send you more XMR as a token of my appreciation?