Pursuant to The Small Business Jobs Act of 2010, Solo 401(k) Plan participants or employees can now convert of a traditional 401(k) or 403(b) account to a Roth 401(k) in the same plan if their employer offers one. Converting a traditional 401(k) account to a Roth 401(k) account will offer the same one-time tax perk as Roth IRA conversions in 2010.