Apple's next major update to Mac OS X is starting to appear in web logs, according to MacRumors.
Bug reports from the early builds of Mac OS X 10.7 were spotted from November of last year. Mac OS X 10.7 signatures have also started appeared in logs from Apple-owned IP addresses, including MacRumors own web logs.
Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_7; en-us) AppleWebKit/532.7.1 (KHTM L, like Gecko) Version/4.1 Safari/532.7.3
John Gruber from Daring Fireball has heard that Mac OS X 10.7 will be ready for developer release by WWDC this June.
OS X 10.7. I'm anxious to know the OS name. The image posted may not be a the actual one but it has a resemblance to a lion. Just a little speculation.