The Star Trek Online Website now offers system requirements for Cryptic's upcoming Trekkie MMORPG. There's also a Star Trek Online Interview on NowGamer talking in detail with Craig Zinkievich about the game. Here are the system specs:

System Requirements
OS: Windows XP SP2 / Windows Vista / Windows 7 (32 or 64-bit)
CPU: Intel Core 2 Duo 1.8 Ghz or AMD Athlon X2 3800+
Memory: 1GB RAM
Video: NVIDIA GeForce 7950 / ATI Radeon X1800 / Intel HD Graphics
Sound: DirectX 9.0c Compatible Soundcard
DirectX: Version 9.0c or Higher
HDD: 8GB Free Disk Space
Network: Internet Broadband Connection Required
Disc: 6X DVD-ROM

Recommended System Configuration
OS: Windows XP SP2 / Windows Vista / Windows 7 (32 or 64-bit)
CPU: Intel E8400 Core 2 Duo or AMD Athlon X2 5600+
Memory: 2GB RAM+
Video: NVIDIA GeForce 8800 / ATI Radeon HD 3850+
Sound: DirectX 9.0c Compatible Soundcard
DirectX: Version 9.0c or Higher
HDD: 8GB Free Disk Space
Network: Internet Broadband Connection Required
Disc: 6X DVD-ROM