"The Price of a Voter Database"

Jurriaan Bendien, Marxmail

In brief, it's expensive, although possibly a university might get a license
at a discount. Some options listed here.

Caliper's Maptitude for Redistricting is said to cost about four thousand
dollars per copy. The software permits mapmakers to analyze a large amount
of data-party registration, voting patterns, ethnic makeup from census data,
property-tax records, roads, railways, old district lines.

Maptitude

ESRI's ArcView geographic information system has an extension that automates
the redistricting process. The Districting Extension lets you manually move
boundaries, and instantly see the statistical result in table or chart
format. A redistricting wizard can automate the process even further. You
can set target values for quantities such as population for the software to
optimize, and then view statistics of the results. This lets you create
alternative redistricting scenarios.

Arc

ArcView

There's also Voter Vault, used by the Republicans.

Voter Vault

More news here.

Some other possibilities:

VotersOnLine

Voter Access

Adjutant

AlphaSoft

Esit