I'm sure it exists -- I am asking specifically if there are any good places near the Narai Hotel on Silom Rd? Or, in general, near skytrain stations??

You will find internet cafes absolutely 'everywhere', very popular. Do not expect fast connections though Bangkok is certainly faster than other parts of the country where connections are often amazingly slow. Costs anything from B40-B100 for 1 hour.

I was just in Bangkok, and I used the internet at the tourist office in the Saphan Taksin Skytrain station (this is the one right on the river, where most of the big hotel shuttles drop you off .. I was staying at the Marriott Resort). It was pretty cheap (no more than 40 baht for 15 minutes), though the connection was a little slow.

the avarage charge is about 30 baht per half hour.. but you can find places that charge 30 baht an hour..

I''d suggest checking out any one of the large shopping malls connected to the Skytrain. At the Emporium mall, there is an internet cafe on the 4th level with a fairly fast connection and at least 12 booths. I'm sure you can find others.