I haven't seen any bass tabs for Hey Rosetta so I figured I'd take a stab at one of 
them. I might do a couple more since the bass is sooooo good!

Intro:

G----5-5-5-5-|
D------------|
A-3~---------|
E------------|

Verse 1 (x2):

G-----------------------------------------------------|
D-----------------------------------------------------|
A-3--3-3--3-5-5-5-7--7--2--3--3-3--3-5-5-5-7--7-10-10-|
E----------------------3------------------------------|


G----------------------------------------|
D----------------------------------------|
A-3-3-3--5h7------2---3-3-3--5h7-------2-|
E------------0-0-3---------------0-0-3---|


G-------------------------------------------------|
D-------------------------------------------------|
A-3-3-2-2-0--------------2-3-3-2-2-0------------2-|
E-----------3-0-0-2-2-3--------------3-0-0-2-2-3--|

Chorus (x2):

G------------------------------------------------|
D------------------------3-3-3-3-5-5-2-2-2-0-----|
A-0-0-0-0--2-3-3-3-3-5-7---------------------3-2-|
E---------3--------------------------------------|

Pre Verse 2:

G------------|
D------------|
A-0-0-0-0--2-|
E--------3---|

Verse 2:

G-----------------------------------------------------|
D-----------------------------------------------------|
A-3--3-3--3-5-5-5-7--7--2--3--3-3--3-5-5-5-7--7-10-10-|
E----------------------3------------------------------|


G----------------------------------------|
D----------------------------------------|
A-3-3-3--5h7------2---3-3-3--5h7-------2-|
E------------0-0-3---------------0-0-3---|


G-------------------------------------------------|
D-------------------------------------------------|
A-3-3-2-2-0--------------2-3-3-2-2-0------------2-|
E-----------3-0-0-2-2-3--------------3-0-0-2-2-3--|

Chorus 2:

G------------------------------------------------|
D------------------------3-3-3-3-5-5-2-2-2-0-----|
A-0-0-0-0--2-3-3-3-3-5-7---------------------3-2-|  (x2)
E---------3--------------------------------------|

G------------------------------------------------|
D------------------------3-3-3-3-5-5-2-0-2-0-----|
A-0-0-0-0--2-3-3-3-3-5-7---------------------3-2-|
E---------3--------------------------------------|

After the little instrumental break-down:

G-----------------------------------------------------------------|
D-----------------------------------------------------------------|
A-0-0-0-0-0-0-0-0-3-3-3-3-3-3-3-3---------------------------------|
E---------------------------------0-0-0-0-0-0-0-0-3-3-3-3-3-3-3-3-|

Chorus 3 (Ending):

G------------------------------------------------|
D------------------------3-3-3-3-5-5-2-2-2-0-----|
A-0-0-0-0--2-3-3-3-3-5-7---------------------3-2-|  (x2)
E---------3--------------------------------------|

G------------------------------------------------|
D------------------------3-3-3-3-5-5-2-0-2-0-----|
A-0-0-0-0--2-3-3-3-3-5-7---------------------3-2-|
E---------3--------------------------------------|

During the last 15 or 20 seconds of the song the bass changes a little bit. I never 
bothered to figure that part out.
I think this is pretty near correct, with the exception of a few parts I wasn't entirely sure of.