He has "resigned" and has been made the Steward and Bailiff of the Manor of Northstead, nothing to do with the Chiltern Hundreds, a separate but similar entity IIRC. It's Ian Gibson (the ex-Norwich North MP) who holds the office of Crown Steward and Bailiff of the Chiltern Hundreds.
The campaigning for the by-election is underway, but it will now not be held until November at the earliest. Candidates have been declared for BNP, Labour, SNP, SSP, Solidarity and SSCUP. Tories and Lib Dems may not bother as this area is Labour through and through. That said, given SNPs success next door a few, I think Labour may struggle. I think that's their real reason for delaying the by-election.
And, by the way, he has never lived in the Gorbals.