Introducing 3E

[Olgar Shiverstone]

Necromancer's Lost City of Barakus will provide you with almost a full campaign for them to get started in.

 

[Andre]

NeMoren's Vault is quite good, and I think they have a 3.5e version available as a PDF on their website (Fiery Dragon Games).

Thirded.

 

[meomwt]

NeMoren's Vault revised for 3.5e available at the Firey Dragon Downloads shop.

The original 3.0e version is also available at their Adventures page. And there's a free epilogue adventure available as well.