Hi,
No, you have to compile truecrypt yourself. I have done that but it does not work to mount an encrypted volume for some reason, It looks like dm_crypt is not working properly.
EDIT:
OK, now I have finally got TrueCrypt to work. I am mounting volumes with the option: '--mount-options=nokernelcrypto'. This will use the TrueCrypt's internal crypto API's instead of the kernel's. I dont know why the kernel API's doesnt work. I think it has something to do with the ARM processor and patches might be needed for the kernel.
I´ve run samba speed tests using an encrypted volume and a normal disk mount (unencrypted) the truecrypt speed is not that satisfying to me, kinda makes me sick

Without encyption: ~28-35 MB/s
With encryption (AES): ~5 MB/s
I guess I wont be using the Sheeva as a small power-efficient encrypted file server.