As Carrol notes, lust is in the second circle, right after limbo.  It is the least of sins because it is "not wholly selfish" [Sayers]; it is a kind of perversion of love.  It has nothing to do with fraud.
I cannot find any suggestion in "Prufrock" that the women are lustful.  If anything, they are mocked for imagining themselves to be knowledgeable about Michelangelo.  Desire is attributed consistently to Prufrock himself, though he can never act on it.  It is he who thinks in phrases from "To His Coy Mistress" and imagines women's arms and hair and perfume.  There is not a single image of a woman being, thinking, or acting lustful in the poem.
When Eliot wrote this, he was 22-23 and a virgin.  He wrote to Conrad Aiken when he was 26 about his own desires rising up and disturbing him; he got married suddenly the following spring. 
I cannot imagine on what lines or images or words one could attribute the "lust" in "Prufrock," which seems about a singular inability even to express desire, to the women Prufrock obsesses about.

>>> Carrol Cox <[log in to unmask]> 02/08/10 9:19 AM >>>
Chokh Raj wrote:
> [contd.]
> In the epigraph, Montfeltro would reveal his sin of fraud to Dante
> because he thinks Dante belongs with him to hell -- that there would
> be no fear of infamy involved in sharing his state of sinfulness with
> him.
> In the monologue, like Dante, Prufrock is a visitor to this den of
> lust/sin.

Apparenly yo've never bothred to read Dante, who is careful to demarcate
his various categories of sin. And of course he put the sin of lust in
upper heel, the lesser sins. It is notable that the lovers damned there
ar _anxiousd_ to have their story told. Fraud is a much more serious sin
than lust.

Better go back and read the five or six opening cantos of Hell, then
reread what Dante says about all of lower hell in geneeral, and frud in
particular. Why in the world would you make such a simple error in re
gard to Dante as this?