I'd say the 5600Ultra should be available by the 2nd week of July .
The clock speeds of the newer model are : 400/400
I'm suppose that BFG will be the first out with these also, since they were with the 5900 Ultra

Copy/Paste from BFG website below .
Coming soon?estimated availability July, 2003
"Dearest friends outside The Institution ? I waited for the nurses?watching them under the door to my cell.
They want to take away my latest creation, the Asylum? GeForce? FX 5600 Ultra. But I won?t let them. this
card is for you, the gamer who wants the most! I designed this graphics card to play the most recent
Microsoft® DirectX® 9.0 games and applications with cinematic-quality visuals and blistering fast performance."
Specifications
? GPU NVIDIA® GeForce? FX 5600 Ultra
? Bus Type AGP
? Memory 128MB DDR
? Core Clock 400MHz
? Memory Clock 800MHz (Effective)
? RAMDAC Dual 400MHz
? API Support Microsoft® DirectX ® 9.0, OpenGL for Microsoft® Windows®
? Connectors VGA, DVI, S-Video Out
? 100 million vertices/sec.
? 12.8GB/sec. memory bandwidth
Minimum System Requirements
? Intel Pentium®III, AMD® Duron? or Athlon? class processor or higher
? 128MB of RAM
? 250 watt min./300 watt recommended power supply
? An available 2.0 or 3.0 AGP slot
? An available 4-pin hard drive power connector from internal power supply
? CD or DVD-ROM Drive
? 10MB available hard disk space (50 MB for full installation)
? Microsoft® Windows® 95 OSR2, 98 or higher, ME, 2000, XP, NT4.0 with service pack 5 or 6
Features at a Glance
? AGP 8X (compatible with 4X and 2X AGP 2.0
compliant slots)
? Up to 4 pixels per clock rendering engine
? Up to 16 textures per pass
? NVIDIA® Intellisample Technology
? NVIDIA® Digital Vibrance Control? 3.0
? Vertex Shader 2.0 and Pixel Shader 2.0
? 128-bit, studio-precision color Included in Box
? Asylum? GeForce? FX 5600 Ultra graphics card
? Quick install manual
? DVI to VGA connector
Driver CD, which includes;
? NVIDIA® unified drivers
? NVIDIA® GeForce? FX and GeForce?4 demos
? Full installation manual .pdf
? NVIDIA® NVDVD? 2.0 multimedia software
? Windowblinds? BFG / Asylum Windows XP skins