If you have Express Tools try "Explode Text".
Or try this lisp:
; TIP #637 XTEXT.LSP By Ashoke Bhattacharya CADalyst Magazine March 1991
; ------------------------------------------------------------------------
; DESCRIPTION: Explodes a line of text into its component letters.
; ------------------------------------------------------------------------
(princ "\nStart command with XTEXT.")(graphscr)(princ)
; ------------------------------------------------------------------------
(defun C:XTEXT ()
(setvar "CMDECHO" 0)
(setq A1 (entget (car (entsel
"\nSelect text: "))))
(setq A2 (cdr (assoc -1 A1)))
(command "ERASE" A2 "")
(setq A (cdr (assoc 1 A1)))
(setq SP (cdr (assoc 10 A1)))
(setq HT (cdr (assoc 40 A1)))
(setq B (strlen A))
(setq B1 1)
(repeat B
(setq C (substr A B1 1))
(command "TEXT" SP HT 0 C)
(setq B1 (+ B1 1))
(setq HT1 HT)
(if (= 108 (ascii C))
(setq HT1 (/ HT 2)))
(if (= 105 (ascii C))
(setq HT1 (/ HT 3)))
(if (= 73 (ascii C))
(setq HT1 (/ HT 1.5)))
(setq SP (polar SP 0 HT1))
)
(redraw)
(princ)