It was a long time coming, but PC World reports that Google Labs has finally added the ability to check Calendar and Docs from within Gmail. 
In the Gmail blog announcing the new features, Gmail engineer Dan Pupius explains that the integration is done via gadgets:
To get you started, we’ve worked with the engineers from the Calendar and Docs teams on two highly requested features: a simple way to see your Google Calendar agenda and get an alert when you have a meeting, and a gadget that shows a list of your recently accessed Google Docs and lets you search across all of your documents right from within Gmail.
Labs also added a third feature, the ability to add any gadget into Gmail by pasting in the URL of its XML spec file, although Pupius says that’s aimed more for developers and “isn’t very user friendly right now.” He also cautioned that some gadgets are not fully compatible with https, so security warnings can be a problem:
“If you’re connecting to Gmail via https, you may see mixed content warnings caused by parts of the gadgets being served over http. We’re working on fixing this where we can.
The new features are just part of a long list of Gmail improvements over the last month (including emoticons, canned responses, and Mail Goggles, among others). Could Google be readying the rollout of a new version of Gmail? In any event, it’s about time that such basic integration between core parts of the Apps suite saw the light of day.
