In a preview of how Howard Dean hopes to use his Internet fundraising network on behalf of Democratic candidates this fall, the former Vermont governor sent out an e-mail fundraising appeal on behalf of Rep. Jesse Jackson Jr. (D-Ill.) over the weekend.

The e-mail solicitation came on the eve of Illinois’ primary today in which Jackson faces a challenge from former Rep. Mel Reynolds and just days before Dean unveils his much-discussed new political entity.

“This is going to be a significant part of what the new organization will do in terms of helping Democratic candidates,” said Dean spokesman Jay Carson.

Neither Carson nor Jackson was able to provide a rough estimate on how much the fundraising appeal generated for Jackson’s campaign.

The Illinois Congressman was a leading advocate for Dean, particularly in the black community, which initially had some concerns about the former Vermont governor’s ability to speak to their issues.

“In good times and bad, when we were up and when we were down, he stood with us and worked hard every step of the way,” Dean wrote about Jackson in the e-mail. “He asked for nothing but an assignment to help us win.

“Now Congressman Jackson confronts his own re-election challenges and we need to help,” Dean added.

Jackson is a heavy favorite in the primary against Reynolds and enjoys an overwhelming financial advantage in the contest.

Through Feb. 25, Jackson had disbursed $403,000 on the race and had $704,000 left to spend.

Reynolds had not even filed a report detailing his finances with the Federal Election Commission, which is required for any candidate raising or spending more than $5,000.

Reynolds held the Chicago-based 2nd district from 1992 until he resigned in 1995. He was later imprisoned for having sexual relations with a teenage campaign worker.

The fundraising plea on behalf of Jackson is the second time that Dean has attempted to use the Internet donor base that helped him raise more than $50 million for his presidential campaign to boost Democratic House incumbents.

The first effort came on behalf of Iowa Rep. Leonard Boswell (D) at the zenith of Dean’s momentum in the presidential race.

In a 24-hour period in early December, Dean givers chipped in $52,000 to Boswell’s re-election campaign — roughly one-third of the $143,000 the Democrat had raised from individuals in the first nine months of 2003.

Dean’s then-campaign manager Joe Trippi, said the campaign had plans in the works to raise funds for a variety of vulnerable Democratic incumbents after the former Vermont governor sealed the nomination.

That day never came, as Dean placed a distant third in Iowa, second in New Hampshire and won no primaries on Feb. 3. Dean dropped from the race in the days following the Feb. 17 Wisconsin primary.

Since that monumental collapse, Dean has largely stayed out of the limelight, seeking to mend fences with his former opponents including Massachusetts Sen. John Kerry (D) — the party’s standard-bearer against President Bush in November.

In an e-mail to supporters late last week, Dean sounded a conciliatory note about a recent meeting with Kerry.

“During the campaign we often focused on what divided us, but the truth is we have much more in common beginning with our fervent desire to send George Bush back to Crawford, Texas,” Dean wrote.

Dean will formally announce his plans to form a new political organization on Thursday.