This is a great time of year for Enghlish Bitters and other lighter ales. With more experience I suggest the real challenge of decoction mashing with 6-row to produce a Continental Pilsner. But for now the wheat beer is a great plan.
Brewing a wheat beer is not such a big deal but a Berliner Weisse can pose some problems. Many beers of this style use a very high barley to wheat ratio. The beers' best benefit from this is a great foam. But the mash can be gummy and this can result in a stuck mash. Certain beers are aided by use of rice husks in the grain bed to aid wort run-off Berliner Weisse is one of them. The other thing is to be sure to use a proper yeast strain. This top fermented wheat beer is aided with warmer fermentation temperatures and both the yeast and Lactobacillus fermentations. You want good ester production and the yeast is key to this. The above link to Wyeast labs have some good examples. You might also consider yeast blending with some Belgian sour beer strains.
White Labs
WLP300 Hefeweizen Ale Yeast
This famous German yeast is a strain used in the production of traditional, authentic wheat beers. It produces the banana and clove nose traditionally associated with German wheat beers and leaves the desired cloudy look of traditional German wheat beers.
Attenuation: 72-76%
Flocculation: Low
Optimum Fermentation Temperature: 68-72°F
Alcohol Tolerance: Medium
* WLP351 Bavarian Weizen Yeast
PLATINUM STRAIN – July/August
Former Yeast Lab W51 yeast strain, acquired from Dan McConnell. The description originally used by Yeast Lab still fits: "This strain produces a classic German-style wheat beer, with moderately high, spicy, phenolic overtones reminiscent of cloves."
Attenuation: 73-77%
Flocculation: Low
Optimum Fermentation Temperature: 66-70°F
Alcohol Tolerance: Medium