Anticipated date for a "multiplayer alpha" (essentially skirmish multiplayer without any of the persistence elements) is 12 months.
The beta for the single player campaign "Squadron 42" is scheduled for 18 months from now, with a final product release in two years. The persistent world will presumably be in a beta phase by then, and will be ramping up to a feature complete game by mid-2015.
Any crowdfunding pledges that have the game as a reward (the full packages starting at $35, now, since the $30 early bird ones are sold out) will grant access to the alpha and beta.
If you opt not to contribute during the crowdfunding, the full game will release with a $60 pricetag or thereabouts.
The pledges generally work like this: the $30-40 pledges have the same rewards, the less expensive ones are just limited in quantity as incentives to get in before they run out. They offer alpha and beta access, and a game account with the RSI Aurora ship (which is presumably the starter ship that retail copies will get).
Higher tiers of pledges replace the Aurora with a different ship as your starter ship: the Origin 300i at $60, your choice of the Anvil Hornet or the MISC Freelancer at $125, and then all the pledges from $250 and up offer the RSI Constellation.
A development document with detailed specs of the ships can be found
at this link, but I'll summarize here. The Aurora is a small all-arounder. The 300i is a larger all-arounder with more upgrade capacity. The Hornet is a dedicated dogfighter. The Freelancer is a small trade and exploration vessel that can be crewed by 2. And the Constellation is the largest pledge reward ship, featuring a crew of up to 4 and sporting the most armaments and largest cargo hold of the 5 pledge ships. It also comes with and docks a dedicated short-range fighter that is not jump-capable.
The $125 tiers and up come with one of three hardcover books -- a book of technical goodies related to the campaign comes with the Hornet's pledge, a book geared towards helping modders get up to speed modding the game comes with the Freelancer, and a behind the scenes "making of" comes with the Constellation pledges.
Different pledge levels come with different color Citizen Cards, plastic (or, if you're a big spender, metal!) credit-card style cards that can be printed with your or your character's name and will be similar to the ID cards issued to citizens in-fiction. These are mostly trinkets geared towards collectibility, though it's been suggested that there might be "fun" or discount-related applications should Star Citizen ever have its own convention, SOE Live or BlizzCon style.
Um, I think that about covers it. Oh, wait. Ship-styled USB sticks for $125 and up, and a small (3-8", IIRC) physical miniature model of the Constellation in increasing sizes for the Constellation pledges.
Oh, and pledging via a referral link (like
this one here) gets you some bonus in-game credits and enters you in daily and end-of-funding-drive drawings to win some hardware. If you want to pledge via Kickstarter (and help with the current stretch goal to get two more ships added to the game by launch), you'll miss the daily drawing, but can still enter a referral when the Kickstarter ends.