There are still many great Sims 1 websites, some old and some new with active creators. Some of these are listed below and I hope gradually the list will increase :)

(Older Sims Downloads are archived in many places online.

CTO Sims was the best place, with many many files and a wonderful creative community. Will, I hope, be resurrected soon.)

Simblesse Oblige has some, and Neighbourhood 99 and TerraLuna.

Yahoo Groups.

Sims Architectural Supplies tutorials! wonderful buildings      
Around the Sims everything!      
Awesome Expression        
Biedersims   Gothy and dark items including a vampire hack    
Corry's Factory nice anime skins great Asian looking heads    
Marina's Sims   wonderful build mode objects    
  Nimi's   Amazing skins    
OddSim hacked objects      
  Oph3lia's Little Page About the Sims lovely objects and builds "You may freely clone ONLY the following items without asking (as long as you give credit): The faux roof tiles, The Gableroofs,The faux corner windows, The Curtains, The Haversham Shutters, &theCircle painting template. No other objects may be cloned without permission."    
Sim City Mental Institution great heads      
SimFreaks objects, skins, meshes      
Sims Peaceful Days        
Some SimThings hacked objects, tutorials      
Watersim YMDesigns awesome clothing      

Secret Society of the Woobsha hacked things, tutorials! mostly clonable with a link back