With the latest upload of GRUB 0.97-58 to unstable, the upgrade path is set to GRUB2.

If you want to continue using GRUB Legacy, it is now provided in the grub-legacy package that will continue being supported at least until the Squeeze release. You just need to uninstall the grub dummy package and keep upgrading the mentioned grub-legacy package happily.

Update: Grub maintainers have sent a Bits from the GRUB maintainers email and there is also a wiki page to track this release goal.