Söderling enjoyed a 6-3, 7-5 win over a typically feisty Radek Stepanek in the first semi-final, before defending champion Roddick overcame big-serving South African Kevin Anderson in three sets 6-2, 4-6, 6-2 in the other.
Söderling, the first top-five player from Sweden in a decade, will go into the final as slight favourite after giving a serving master class during his win over Stepanek.
He broke the Czech early in both sets and was untroubled on his own serve until inexplicably stumbling while serving for the match at 5-4 in the second.
Stepanek seized on his only break point opportunity in the match to level the set at 5-5, only to drop his own serve immediately and hand the initiative back to Söderling.
This time, the 26-year-old world number five made no mistake as he comfortably held to wrap up an entertaining match.
"I've served well and played well the whole week. I think today was my best match," an upbeat Söderling said later.
Söderling said he became too conservative when he got the chance to serve for the match the first time.
"I missed a couple of easy shots but at the same time he played really well. Maybe I didn't go for my first serve as much as I should have -- I tried to put it in but he returned very well," he explained.
"I think it was a mix of me playing a little bit too safe and him playing very well," added Söderling.
Roddick opened his semi-final strongly against a nervous-looking Anderson, breaking the South African twice on his way to a 4-0 lead.
Anderson recovered and gradually came into the contest, beginning to dominate during the second set and breaking the American at 5-4 to level the match.
However, he seemed to lose concentration at the start of the third and Roddick pounced, breaking Anderson twice to again race to 4-0 before comfortably serving it out to take the match.
"I felt like I was in control pretty much the whole match, even in the second set I played one bad game but I thought I had more looks at his serve than he had at mine. I actually broke more than I thought I would against his serve," said Roddick.
Roddick said he expected that the final would bring out the best of both men.
"We're going to see the best of what we've seen this week. He's playing great, he served real well today. He was in control of that whole match -- he's been in control of all his matches this week," he said.