Our package arrived in a cardboard box with the Crucial sticker on the front with some basic info on the memory modules that were supplied. Our kit was the new 2GB variant with 2 x 1GB modules for Dual Channel systems. Dual Channel has been around for ages now, and has proven to be just what the doctor ordered especially for the Intel platform which can support extremely high bandwidth memory across its quad pumped FSB.
Crucial Ballistix memory modules are rated from the factory to run at speeds of 1000MHz DDR with a timing profile of 5-5-5-15, which is the highest latency set that the DDR-2 memory standard provides. These ratings are for the modules at 1000MHz, so usually if you want to run the modules at lower speeds with tighter timings, generally this is easily obtainable. The modules also are rated to a maximum voltage of 2.2v without voiding your warranty, that's a +0.4v increase over default. Most boards these days go beyond that, so if you want to go higher you will void your warranty.
When it comes to marking on the modules, Crucial has really kept it low key - in fact, there are no actual specs of the memory speed or timing ratings. For these you need to use the model number that is printed on a small piece of sticky paper attached to the heatsink and check the Crucial website to get any relevant info on the modules.