Use the ListQualify() function to pass a list of strings to the where argument in CFWheels ORM finders. ListQualify() encloses each list element in with the string specified (in this case, a single quote). Without it, CFWheels interprets the list as a single value.

<cfscript>
names = "Foo,Bar";
users = model("User").findAll(where="firstname IN ('#names#')");
/*
 * Generates SQL Query.. Not so good
SELECT firstname, lastname FROM users WHERE firstname IN ('Foo,Bar')
*/

users = model("User").findAll(where="firstname IN (#ListQualify(names, "'")#)");
/* 
 * Generates SQL Query. Great success!
SELECT firstname, lastname FROM users WHERE firstname IN ('Foo','Bar')
*/
</cfscript>

Great success!