There are two variants of toasters to be found in Fallout 3 and Fallout: New Vegas, a pre-War and a post-War version. The pre-War version is much rarer in both games. In Fallout 3, toasters can be used for Rock-It Launcherammunition.
The following is based on unverified behind the scenes information and has not been confirmed by canon sources.
In Fallout 3, after disarming the nuke in Megaton, Three Dog mentions that his toaster needs repair on the radio when describing the player character's exploit. It may be a subtle reference to Wasteland's skill toaster repair, where the player character could repair broken toasters for various items.
The design of the toaster resembles the 1909 Simplex T211 toaster, a two-slice side-loading model which toasts one side of the bread at a time.
End of information based on unverified behind the scenes information.