PLT CONTINUED VFR INTO IMC. DSCNT TO DEST ACCOMPLISHED BY REF TO GPS.

Narrative

I WAS ON A VFR FLT FROM 1V5 (BOULDER) TO GXY (GREELEY WELD; CO); DIRECT; NAVING BY GPS; VISIBILITY 20 MI AND CLR SKY. AT 17 NM OUT; I ENCOUNTERED HAZE REDUCING VISIBILITY TO APPROX 8 NM. I CONTINUED INBOUND ON A COURSE OF 038 DEGS. AT ABOUT 10 NM OUT; I CALLED GXY UNICOM AND ASKED IF THEY WERE VFR OR IFR AND THEY INFORMED ME THAT THEY WERE VFR. AT 7 NM OUT THE HAZE REDUCED VISIBILITY TO ABOUT 5 NM. I ONCE AGAIN CONFIRMED WITH GXY THAT THEY WERE VFR. I CONTINUED INBOUND ON COURSE; AND ENCOUNTERED A 090-100 DEG WIND AT ABOUT 15-20 KTS. THE WIND WAS VERY EVIDENT BECAUSE I WAS BLOWN TO THE L OF COURSE. THE HAZE CLRED MOMENTARILY AND VISIBILITY IMPROVED TO 10-15 NM; WITH ARPT IN SIGHT. THEN AS QUICKLY AS THE VISIBILITY HAD CLRED; THE VISIBILITY WAS REDUCED TO ZERO AND CONDITIONS WERE 100 PERCENT IMC. I REALIZED THAT I WAS BLOWN OFF COURSE OVER THE CITY OF GREELEY; CO; AND WAS AT 5600 FT AND HAD STARTED TO LET DOWN FOR ARPT PATTERN ALT. MY THOUGHT WENT TO TWRS AND HIGH BUILDINGS; I COULDN'T REMEMBER THEIR HT. TO BE SAFE; I PUT IN FULL PWR AND STARTED TO CLB. I THOUGHT; 'LOOK AT THE ARTIFICIAL HORIZON (ALT INDICATOR) -- STOP FIXATING ON THE GPS!' I WAS IN A CLBING TURN TO THE L. I THEN LEVELED OFF AT 5900 FT MSL; AND CHANGED COURSE TO 360 DEGS. I WAS 4.3 NM W OF ARPT PER THE GPS. I GAVE A POS RPT AND THEN CONFIRMED THAT GXY WAS STILL VFR AND THEY CONFIRMED THEY WERE VFR; AND THAT THEY HAD ESTIMATED CEILINGS OF 800- 1000 FT AGL. I CONTINUED N UNTIL I WAS NW OF GXY. I THEN TURNED 090 DEGS AND STARTED TO LET DOWN AT ABOUT 100 FPM. AT 2.7 NM NW OF GXY I BROKE OUT AT 5600 FT MSL. I SAW THE APCH LIGHTS FOR RWY 9. DECLARED TURNING R TO ESTABLISH L BASE FOR RWY 9 AND LANDED WITHOUT FURTHER EVENT. MY THOUGHTS: I SHOULD HAVE ASKED FOR THE DEWPOINT AT GXY TO BE AWARE OF THE POSSIBILITY OF RAPID FOG AND CLOUD FORMATION AND USED THE INFO AS AN INDICATOR TO NOT CONTINUE INTO MARGINAL VFR CONDITIONS. WHEN VFR PLTS ARE SHOCKED BY IFR CONDITIONS; STOP FOCUSING ON THE GPS BECAUSE IT ONLY GIVES POS; AND FOCUS ON THE INSTS THAT INDICATE AIRPLANE ATTITUDE. MY PLANE IS IFR EQUIPPED; BUT NONE OF THE EQUIP WAS TUNED IN OR TURNED ON. IT IS VERY DIFFICULT TO TUNE A GS WHEN YOU ARE CONCENTRATING ON ATTITUDE INSTS. LASTLY; I FEEL MANY PLTS HAVE FORSAKEN VORS; MARKER BEACONS; AND GS FOR GPS.