Gmail recently launched two new labs features. Both the feature are highly requested by users and google granting them. One feature is nested labels.It gives you the ability to organise labels hierarchically.It just like making folders inside a folder to organise your data. like you have a folder names entertainment then inside that folder you have various other folders like movies, songs, pics, videos etc. So this nested label also works on this way.
Another interesting feature included is message sneek peek which lets you preview messages in your inbox much like that of google reader in igoogle if you have tried one. The google reader in igoogle works a lot better than the sneek peek in gmail. Well nevertheless it was a highly demanded feature which gmail user used to miss, as yahoo, msn, outlook supports a tri panel design in which you can view your messages without leaving you inbox.
To enable both the features just click in the labs icon in gmail and enable "nested labels" and save it. Say you want to create a new label "movie" under the main label "entertainment", so name the label as "entertainment/movie".
Or see example
To enable "message sneek peek" same as before go to gmail labs and enable "message sneek peek" and save it. To preview a message just right click on the mail .. and vola!! theres the preview.
And hey gmail has also reorganized gmail labs. Now labs features are categorized into enabled ones and those not enabled.