First off, you can get a Namaste ringtone by texting "Namaste" to 77888. Terms and Conditions apply.
Next, there's a clue at Season 5 with the following sounds you will hear in the episodes:
From #501:Thrilling, I'm sure you'll agree... Finally, there's a video where D & C discuss Lost books. They specifically mention "The Stand" by Stephen King as a great book, but also discuss Ulysses by James Joyce - which Ben will be reading in episode 5x07! Perhaps a good read for February's Lostpedia book club? Right at the end of the video, however, is a brief glimpse at a new DHARMA logo (pictured).
CL-CLICK. BEEPBEEPBEEPBEEP. KNOCKNKNOCKKNOCK! WHAPPP! VVVVVVWWHHHHHEEEEMMMMMM! PLLEPPT-PLEPTT-PLEPTT. BOOOOOOOOOM! BLAAM!!! THUUDDD. CRUUUUUUUUUNCH! PFFT! PFFT! PFFT! SMAAASSHHHH! SHCLICK!!!! CA-CLICK. FOOOMP. SKLIIIIIISH. PING. RAT-A-TAT. BAMBAMBAMBAMBAM!!!!
From #502:
BWOOBWOO! TAPTAPTAPTAPTAP. KNOCKKNOCKKNOCKKNOCK. BZZZZZZZZZZZZZ. SLAMMM! THWACK! KRE-KLACK. BEEEEP... SLAMS. SCRRIIIIIDDDDDDDFLIP!
From #503:
FLAPP-FLAPP-FLAPP. AAAAARRRRRRGGGGGHHHHHH!! THRAAAAASH! KAAAAAAAA-THWOOOOOOOOOOOM!!!!! CLICKETY-CLICKETY-CLACK. CRRRR-ACK!
Let theories about lighthouses/street lamps commence.