Borderlands 1 Modding
There’s not much information on here about Borderlands 1 modding, at the moment, since the authors of this page aren’t really involved in that scene. We’d love to at least add in useful BL1 modding links, though, so please let us know what content makes sense to have on here.
As for what’s more obviously available via Google:
A Borderlands 1 Modding Wiki exists, which seems to have a lot of information available on there.
Borderlands 1 on Nexus is at least one place to acquire BL1 mods.
The Borderlands “Fan Creations” GBX Forum is a place where modders can post and discuss their mods.