Those who have already received an invite to try out Google Inbox can now invite their friends to use the service, too. You'll have to choose carefully who you give your invites to, however, because you only get three to give away.

Inbox, which was unveiled by Google for the first time last week, delivers a new take on email. It aims to make your inbox more useful — and more organized — by turning your emails into more then just plain old messages.

You can snooze messages for later so that you don't forget to act on them, pin the ones that are really important to you, and archive everything you're done with. You can also have a to-do list right inside your inbox so that your messages and tasks can be found in one place.

Inbox also categorizes mail for you automatically, a lot like Gmail, to keep it more organized. Those from Facebook or Twitter fall into the Social category, for example, while offers, discounts, and coupons go into Promos. You can also sort mail into categories like Travel, Purchases, and Finance.

We've already gotten our hands on Inbox, and we think it's an amazing email experience — even if it isn't quite ready for prime time just yet. If you've been trying it, too, and you feel the same way, you can now invite your friends to join you in experiencing it early.

All Inbox users now have three invites they can share. To give away yours, simply start a new email from within the Inbox app and tap the "Invite to Inbox" option that's depicted by a golden ticket. You can then select the email address you'd like to send the invite to, and then tap the "Invite" button.

If you haven't yet received an Inbox invitation, you can request yours by emailing [email protected]. It's still unclear when Google intends to make the service widely available to all.