2.5mm headset converter for iPhone 3G

[onebyone]

Does anyone know where I can get an adapter so that I can use my 2.5mm cordless phone headset on my iphone 3g?

 

[9822679]

Does anyone know where I can get an adapter so that I can use my 2.5mm cordless phone headset on my iphone 3g?

not that cordless I guess

 

[V4705]

this is exactly what you need.
3.5mm MALE to 2.5mm FEMALE, with a thin head.
dont use this type with the iphone.

but you cannot be sure your old headset will work with the iphone.