Why amount of hashes is limited?

Just because total amount of hashes in the pack is limited, and noone would be happy to download 1'000'000 random hashes from some joker If one really need more than 1000, he can drop a message to sc@14.by asking to increase limit. Following information is required: forum nick, requested limit, confirm that your hashes are unsalted, approximate hash source (4example 'public hash database managed by me').

Where to download client?

It's being tested now. Our main target for now it to prepare hash database, as it would be impossible to add hashes to first working set once we start.

Is this just for MD5?

No, MD5 - that's just first, simple and most 'debugged' algo. Further targets are Unix MD5 and SHA1.

Is this just for Windows?

Right now it is possible to run SSE2 version under Wine. *nix build would appear later if there would be demand.