AppleInsider, based on a report by MacGenerations:

The TRIM command is part of the ATA interface standard. So far, it appears Apple’s support in Lion is only activated for SSDs shipped by the company and not third party devices, but this is likely to be fleshed out more as Lion develops.

It’d be stupid to think that Lion won’t have TRIM support. Heck, I was surprised it’s not on the Airs.

I don’t think I’ll be getting a new Mac anytime soon, so I certainly hope this gets fleshed out. I still want an SSD for my MacBook Pro.